The Assassination of Archduke Franz Ferdinand & Declarations of war | World War I

Archduke Franz Ferdinand of Austria, the heir probable to the Austro-Hungarian monarchy, and his wife, Sophie, Duchess of Hohenberg, were killed instantly by Gavrilo Princip on 28 June 1914, at Sarajevo. Princip was part of a crew of six assassins led by Danilo Ili that included Muhamed Vaso Cubrilovic, Mehmedbasic, Nedeljko Cabrinovic, Cvjetko Popovic and Trifko Grabez. He is a Bosnian Serb and a member of the secret group known as the Black Hand. The assassination's political goal was to separate Austria-South Hungary's Slav provinces to be merged as Yugoslavia. The motivations of the conspirators were similar to those of the Young Bosnia movement. When Austria-Hungary issued a request to the Kingdom of Serbia, which was partially refused, the assassination precipitated World War I. After that, Austria-Hungary declared war on Serbia, sparking a chain of events that resulted in conflict with most European countries.

The Serbian military conspiracy was orchestrated by Dragutin Dimitrijević, Chief of Serbian Military Intelligence, with the help of Major Vojislav Tankosić and Rade Malobabić, a Serbian intelligence agent. Tankosić provided the assassins with bombs and firearms, as well as training. Malobabić used the same clandestine network of safe-houses and agents to infiltrate weapons and operatives into Austria-Hungary, and the assassins were granted access to the same network.

The assassins, essential members of the underground network, and main Serbian military conspirators who were still alive were all apprehended, tried, convicted, and sentenced. In October 1914, those imprisoned in Bosnia were tried in Sarajevo. On the French-controlled Salonika Front in 1916–1917, the other conspirators were caught and prosecuted before a Serbian court on unrelated fake accusations. Three of the leading military conspirators were executed in Serbia. These two trials and related records provide a great deal of information on the assassinations. Following the dissolution of Yugoslavia, Princip's legacy was reevaluated, and popular perception of him in the successor republics is generally divided along ethnic lines. The assassination of Archduke Franz Ferdinand by Serbian nationalists sets in motion Europe's alliance system. Austria-Hungary declares war on Serbia on 23 July. Between 29 July and 4 August, the remaining powers declare war.

Brief details of the assassination of Archduke Franz Ferdinand of Austria and Sophie, Duchess of Hohenberg

Austria-Hungary was agreed the mandate to occupy and manage the Ottoman Vilayet of Bosnia in the 1878 Treaty of Berlin, while the Ottoman Empire retained official sovereignty. The Great Powers (Austria-Hungary, United France, Kingdom, Italy, the German Empire, and the Russian Empire) recognized the Country of Serbia as a fully sovereign state under this treaty, which was transformed into a kingdom four years later under Prince Milan IV Obrenović. He became King Milan I of Serbia. Serbia's kings, who came from the royal House of Obrenović, which had close ties to Austria-Hungary at the time, were content to rule within the treaty's boundaries. The Serbian Royal Palace was assaulted by Serbian military officers led by Dragutin Dimitrijević in May 1903. The invaders kidnapped General Laza Petrović, the chief of the Palace Guard. They compelled him to divulge the hiding spot of King Alexander I Obrenović and his wife Queen Draga after a violent battle in the dark. Following that, the King has shot thirty times and the Queen eighteen times. The invaders tossed the bodies of King Alexander and Queen Draga out a palace window, effectively removing any possibility of a counterattack by loyalists. When Vojislav Tankosić orchestrated the killings of Queen Draga's brothers, General Petrović was assassinated. From the House Peter I of Karađorđević was installed as the new King by the conspirators.

The new dynasty was more nationalistic, sympathetic toward Russia, and antagonistic toward Austria-Hungary. Disputes between Serbia and its neighbours flared throughout the next decade as Serbia consolidated its power and restored its 14th-century empire. A customs dispute with Austria-Hungary, which began in 1906, was one of these conflicts. In the Bosnian crisis of 1908–1909, Serbia protested Austria-acquisition Hungary's of Bosnia and Herzegovina. Finally, in 1912–1913, Serbia took Macedonia and Kosovo from the Ottoman Empire and drove Bulgaria out of the Balkans. Serbian autonomists in Serbia and Serbs in Austria-Hungary who chafed under Austro-Hungarian rule and whose nationalist sentiments were stoked by Serb "cultural" organizations were emboldened by Serbia's military victories Serbian outrage over the Austro-Hungarian annexation of Bosnia-Herzegovina. One significant example is the Serbian nationalist society Narodna Odbrana, founded on the initiative of Milovan Milovanović in Belgrade on 8 October 1908. It functioned under cover of artistic activities to erode Serb loyalty to the Habsburg monarchy in Austria-Hungary. In the five years preceding up to 1914, lone assassins, primarily Serb nationals of Austria-Hungary, attempted a series of unsuccessful assassinations against Austro-Hungarian authorities in Croatia and Bosnia-Herzegovina. Young Bosnia was a local revolutionary movement in Bosnia-Herzegovina whose goal was the disintegration of Austria-Hungary.

Bogdan Žerajić, an associate of the Young Bosnia organization, attempted to assassinate General Marijan Varešanin, the Austrian Governor of Bosnia-Herzegovina, on 3 June 1910. Žerajić was a 22-year-old Conventional Serb from Nevesinje, Herzegovina, a student at the University of Zagreb's Faculty of Law and frequently travelled to Belgrade. Žerajić was an inspiration to future assassins, notably Princip and his accomplice Čabrinović, because of the five bullets he fired at Varešanin and the fatal one he put in his head. In May 1911, important Narodna Odbrana, notably Dimitrijević and Tankosić, founded the Black Hand, a secret club aimed at establishing a Greater Serbia by "terrorist action." Local revolutionary movements such as Young Bosnia were penetrated by the Black Hand and Narodna Odbrana networks in Bosnia-Herzegovina.

In 1913, Emperor Franz Joseph dispatched Archduke Franz Ferdinand to Bosnia to oversee military drills anticipated for June 1914. Ferdinand and his wife intended to travel to Sarajevo to inaugurate the new state museum following the manoeuvres. According to their eldest son, Duke Maximilian, Duchess Sophie accompanied her husband out of concern for his safety. Franz Ferdinand was a proponent of enhanced federalism and was popularly thought to embrace trialism, which would rebuild Austria-Hungary by merging the Slavic provinces within the empire into a third crown. Because a Slavic monarchy may have been a bulwark against Serb irredentism, those same irredentists saw Franz Ferdinand as a threat. One of Princip's motivations, he eventually admitted to the court, was to impede Franz Ferdinand's planned reforms.

The feast of St. Vitus is celebrated on the day of the assassination, 28 June. It is known in Serbia as Vidovdan and commemorates the 1389 Battle of Kosovo against the Ottomans, during which a Serb assassinated the Sultan in his tent. The heroics of Miloš Obilić, recounting the Kosovo Myth, inspired Princip, Čabrinović, and other members of the Young Bosnia. At the same time, it is known that the Princip understood the complete Petar II Petrović-Njegoš's. Čabrinović was deeply engaged in the Myth, personally associating himself with the Kosovo heroes. The Mountain Wreath is a well-known piece of South Slavic literature that extols the heroic principles and spirit of the Kosovo Myth.

Preparation of Straight Action

Danilo Ilić was a Bosnian Orthodox Serb from Bosnia and Herzegovina. He had previously worked as a schoolteacher and a bank employee. In 1913 and 1914, he existed with and supported his mother outwardly. In Sarajevo, she ran a tiny boarding house. Ilić was the secret leader of Sarajevo's Serbian separatist Black Hand unit. Danilo Ilić arrived at the Serbian listening station at Užice in late 1913 to speak with the officer in charge, Serbian Colonel C. A. Popović. He was a captain and a member of the Black Hand at the time. Ili advocated for the end of the revolutionary organization-building phase and the transition to direct action against Austria-Hungary. Popović sent Danilo Ilić to Belgrade to speak with Colonel Dragutin Dimitrijević, also known as Apis, the Chief of Serbian Military Intelligence. Apis and his fellow military conspirators had seized control of what remained of the Black Hand by 1913.

There have been no accounts of what happened between Ilić and Apis. However, shortly after their meeting, Apis' right-hand man and fellow Black Hander, Serbian Major Vojislav Tankosić, who was in command of guerrilla training at the time, convened a Serbian irredentist planning meeting in Toulouse, France. As a result, Mehmedbašić, a carpenter by trade and the son of an impoverished Muslim noble from Herzegovina, was summoned to the Toulouse assembly. Mehmedbašić was eager to commit a terrorist act to rekindle Bosnia's revolutionary spirit. Various possible Austro-Hungarian assassination targets, including Franz Ferdinand, were considered during this January 1914 discussion. However, the members merely agreed to send Mehmed Mehmedbašić to Sarajevo to assassinate Bosnian Governor Oskar Potiorek.

Police looked for Mehmedbašić 's train for a thief while he was travelling to Bosnia-Herzegovina from France. He threw his guns out the train window because he thought the cops were after him. As a result, he started seeking replacement weaponry as soon as he arrived in Bosnia and Herzegovina.

Franz Ferdinand Selected

Mehmedbašić's attempt on Potiorek was hampered by his search for new weapons. Ilić invited Mehmedbašić to Mostar before he was ready to act. On 26 March 1914, Ilić told Mehmedbašić that Belgrade had cancelled the Governor's assassination expedition. The plan now was to assassinate Franz Ferdinand, and Mehmedbašić was ready for the next mission. Ilić recruited Serbian adolescents Vaso Čubrilović and Cvjetko Popović for the killing just after Easter, as proven by Ilić, Čubrilović and Popović testimony at the Sarajevo trial.

Although an agreement in principle was made immediately, the weapons delivery was delayed for more than a month. The assassins would meet with Ciganović, who would dissuade them. The operation was restarted after Emperor Franz Joseph's health improved. One FN Model 1910 pistol was given to the assassins by Tankosi. In a park outside Belgrade, they practised shooting a few rounds of rare and expensive.380 ACP pistol ammunition.

On 26 May, the remaining weapons were delivered. Major Tankosi, directly and through Ciganovi, provided not just six hand grenades and four new Browning FN Model 1910 automatic pistols. According to the three Belgrade assassins, 380 ACP ammunition, but also money and suicide pills.

Eve of the Attacks

On 27 June, Ilić began distributing the guns. Until that day, Ili kept the Belgrade assassins' identities hidden from his local recruits and vice versa. The three mailed a postcard to Vladimir Gaćinović, the Black Hand Provincial Director for Bosnia and Herzegovina, in France.

Motorcade

Ilić placed the six assassins along the motorcade route on the morning of 28 June 1914. Ilić proceeded down the street, encouraging the assassins to act courageously. From Ilidža Spa to Sarajevo, Franz Ferdinand and his entourage took the train. At Sarajevo station, Governor Oskar Potiorek received the party. Six vehicles were parked nearby. Three local police officers were mistakenly placed in the first car with the chief officer of exceptional security, leaving the special security personnel intended to accompany their chief behind. Sarajevo's Mayor and Chief of Police rode in the second automobile. A Gräf & Stift 28 or 32 PS open sports car was the third car in the motorcade with its top folded. This third automobile carried Franz Ferdinand, Sophie, Governor Potiorek, and Lieutenant Colonel Count Franz von Harrach. The motorcade's first stop on the pre-planned itinerary was a quick tour of a military barracks. According to the schedule, the motorcade was scheduled to depart the barracks for the town hall via the Appel Quay at 10:00 a.m.

Sarajevo's security arrangements were limited. General Michael von Appel, the local military commander, recommended that troops be stationed along the planned path but was advised that this would upset the loyal citizens. The Sarajevo police were entrusted with protecting the visiting group, with just roughly 60 officers on duty on the day of the visit.

Bombing

Mehmedbašić, the first assassin, was passed by the motorcade. Danilo Ilić had positioned him in front of the Mostar Cafe's garden and armed him with a bomb. Mehmedbašić was unable to act. Čubrilović had been stationed next to Mehmedbašić, armed with a pistol and a bomb. He, too, was powerless to intervene. Nedeljko Čabrinović had been positioned on the opposite side of the roadway near the Miljacka River by Ilić, who had armed him with a bomb.

At 10:10 a.m., Franz Ferdinand arrived in his automobile, and Čabrinović detonated his device. The explosive landed in the roadway after bouncing off the folded back convertible cover. The bomb's timed detonator led it to explode under the next car, destroying it and leaving a 1-foot-diameter, 6.5-inch-deep (170 mm) crater with 16–20 persons injured. Čabrinović drank his cyanide pill and dove into the Miljacka river. Because the old cyanide merely caused vomiting, and the Miljacka was only 13 cm deep due to the hot, dry summer, the Čabrinović suicide attempt failed. Čabrinović was dragged from the river by police and violently beaten by the mob before being taken into detention. The parade continued on its way to the Town Hall, leaving the disabled car in its wake. As the motorcade passed them at tremendous speed, Cvjetko Popović, Gavrilo Princip, and Trifun Grabež did nothing.

Town Hall Reception

When Franz Ferdinand arrived at the Town Hall for a scheduled reception, he displayed understandable indications of stress, interrupting Mayor Fehim Curčić's prepared welcoming address to protest. He finally regained his composure, and the mayor delivered his remarks. Unfortunately, Franz Ferdinand had to wait for his speech, still soaked with blood from the wrecked car.

Officials and members of the Archduke's party debated the next course of action. Baron Rumerskirch, the Archduke's chamberlain, suggested that the couple stays at the Town Hall until troops could be brought in to line the streets. Governor-General Oskar Potiorek opposed the proposal, claiming that soldiers returning from manoeuvres would not be dressed appropriately for such responsibilities.

Franz Ferdinand and Sophie postponed their planned visit to the hospital to see the victims of the bombing. Count Harrach took up a position on Franz Ferdinand's car's left-hand running board to shield the Archduke from any attack from the riverside of the street. Photographs of the act outside the Town Hall corroborate this. Franz Ferdinand and Sophie rejoined the motorcade around 10:45 a.m., this time in the third car. General Oskar Potiorek determined that the imperial motorcade should proceed straight along the Appel Quay to the Sarajevo Hospital to bypass the busy city center and secure the pair's safety. Potiorek, on the other hand, failed to inform the drivers of his choice. As a result, Leopold Lojka, the Archduke's driver, made the exact right turn at the Latin Bridge as the two drivers ahead of him. According to historian Joachim Remak, the reason for this is that Potiorek's aide Eric(h) von Merrizzi was in the hospital and thus unable to advise Lojka about the change in intentions and driving path. One of the Archduke's aides urged Sarajevo Chief of Police Edmund Gerde, who had previously warned Potiorek of insufficient security procedures for the imperial visit, to inform the drivers of the new route. Still, he failed to do so due to the turmoil and tensions of the time.

Fatal Shooting

After discovering that the first assassination attempt had failed, Princip considered where he could assassinate the Archduke on his way back to Vienna and settled on a position in front of a neighbouring food shop (Schiller's delicatessen), near the Latin Bridge. The Archduke's motorcade's first and second automobiles abruptly turned right into a side street, abandoning the Appel Quay. Governor Potiorek, who was riding in the third vehicle with the Imperial couple, cried out to the Archduke's driver to stop because he was driving in the wrong direction. The driver slammed on the brakes and reversed, stalling the engine near Princip's location. Then, with a Belgian-made Fabrique Nationale type 1910.380 calibre handgun, the assassin stepped up to the car's footboard and shot Franz Ferdinand and Sophie at point-blank range. According to Albertini, the first bullet struck the Archduke in the jugular vein, while the second hit the Duchess in the abdomen. Princip attempted to shoot himself but was apprehended and detained right away. Princip declared after his imprisonment that he intended to kill Governor Potiorek rather than Sophie.

Sophie was shot and quickly passed out, collapsing across Franz Ferdinand's legs. While being driven to the Governor's mansion for medical treatment, the Archduke also passed out. A severe choking sound caused by bleeding followed these statements. On 28 June 1914 By 11:30 a.m. the imperial pair had died; Sophie had been killed upon arrival at the Governor's mansion, and Franz Ferdinand had died 10 minutes later.

Funeral

The bodies were transferred by battleship SMS Viribus Unitis to Trieste and subsequently by special train to Vienna. The funeral was only for the immediate imperial family, with the dead couple's three children excluded from the few public rites, despite most foreign nobility having intended to attend. The officer corps was prevented from saluting the funeral train, which sparked a brief uprising led by Archduke Karl, the putative successor. The public sight of the coffins was tightly restricted, and even more shamefully, Montenuovo attempted but failed to impose a financial burden on the children. Since the Duchess could not be buried in the Grand Crypt, the Archduke and Duchess were buried at Artstetten Castle.

Aftermath

All of the assassins were apprehended in the end. Members of the infiltration route who helped carry them and their weapons to Sarajevo were tried alongside those in Austro-Hungarian prison. Mehmedbašić was detained in Montenegro but was permitted to "escape" to Serbia, where he joined Major Tankosi's auxiliary, but Serbia imprisoned him in 1916 on additional phoney allegations.

In the hours after the assassination, anti-Serb riots erupted in Sarajevo and other parts of Austria-Hungary until the military restored order. Anti-Serb pogroms and demonstrations were held across the Austro-Hungarian Empire on the night of the assassination, mainly in the region of modern-day Bosnia and Herzegovina and Croatia. Oskar Potiorek, the Austro-Hungarian administrator of Bosnia and Herzegovina, planned and encouraged them. The first anti-Serb rallies were held in Zagreb in the early evening of 28 June, led by adherents of Josip Frank. The next day, anti-Serb demonstrations in Sarajevo were increasingly violent, bordering on a pogrom. Anti-Serb violence was not prevented by the city's police and local officials. Sarajevo's violence has been dubbed the "Sarajevo frenzy of hate" by writer Ivo Andrić. On first day of the event in Sarajevo, two Serbs were murdered, many were attacked, and over 1,000 Serb-owned homes, stores, schools, and institutions, including banks, hotels, and printing companies, were razed or pillaged.

Following the killing, Franz Joseph's daughter, Marie Valerie, reported that her father displayed greater faith in his grandnephew Archduke Charles, the new heir presumptive. Regarding the assassination, the emperor admitted to his daughter.

Sarajevo Trial

Except for Mehmedbašić, who had escaped to Montenegro and was released from police custody there to Serbia, the Sarajevo assassins were apprehended and punished by Austro-Hungarian authorities, with the agents and peasants who had aided them on their way. The majority of the defendants were accused of conspiring to commit high treason in the Kingdom of Serbia through official circles. The maximum sentence for conspiracy to conduct high treason was death, although conspiracy to commit simple murder did not. The trial took place from 12 October to 23, 1914, with the verdict and penalties delivered on 28 October.

The adult defendants, who were facing the death penalty, pretended that they were unwitting participants in the plot at trial. The trial of defendant Veljko Čubrilović, a Narodna Odbrana operative who assisted in transporting the weapons, exemplifies this endeavour. Under questioning from defence counsel, Čubrilović went into greater detail about the worries that motivated him to work with Princip and Grabež. Čubrilović claimed that he was frightened that a revolutionary group capable of committing tremendous crimes was behind Princip and that if he did not comply, his house would be destroyed. Moreover, his family was slain, and that he knew such an organization existed in Serbia at one point.

To dispute the claim, the Belgrade conspirators, who did not face the death penalty due to their youth, focused during the trial on putting the blame on themselves and deflecting it from official Serbia and correspondingly adjusted their court testimony from their past depositions. Cabrinović, on the other hand, stated that the political beliefs that drove him to assassinate Franz Ferdinand were shared in the Serbian circles in which he moved. The court did not believe the defendants' claims that official Serbia was blameless. The decision was made. According to the court, the evidence shows that both the Narodna Odbrana and the military circles in control of the intelligence service in the Kingdom of Serbia collaborated in the outrage. The following are the prison terms, death sentences, and acquittals:

Table: Prison terms, death sentences and acquittals

Čabrinović expressed regret for the murders during his trial. Following his imprisonment, Čabrinović received a letter of unconditional forgiveness from the three orphaned children the assassins had orphaned. In prison, Čabrinović and Princip perished of disease. Under Austrian-Hungarian legislation, those under the age of 20 at the time of the crime might get a utmost sentence of 20 years in jail. The court considered arguments over Princip's period because his accurate date of birth was disputed. Still, it was determined that he was under the age of 20 at the time of the assassination. Since Bosnia and Herzegovina had not yet been transferred to either Austria or Hungary, the Austro-Hungarian Finance Minister was in charge of administering the country and proposing clemency to Kaiser Kaiser Wilhelm II.

Salonika Trial

Secret peace discussions between Austria-Hungary and France took place in late 1916 and early 1917. Parallel conversations were placed between Austria-Hungary and Serbia, with Prime Minister Pašić sent his righthand man Stojan Protić and Regent Alexander posting his amigo Colonel Petar Živković to Geneva on secret business, according to circumstantial evidence. The significant demand for Serbia's return to the Serbian Government's supervision in Exile was that Serbia provides guarantees that no future political agitation would emanate from Serbia against Austria-Hungary.

Regent Alexander and his loyal officers had plotted for some time to eliminate the military clique led by Apis, as Apis posed a political threat to Alexander's control. The Austro-Hungarian peace desire gave this idea a boost. Apis and his loyal officers were indicted on several false charges unconnected to Sarajevo on 15 March 1917. On the French-controlled Salonika front, the case was retried before the Supreme Court of Serbia in 1953, and all accused were acquitted by Serbian Court Martial. Apis and eight of his friends were condemned to death on 23 May, while two were given 15 years in jail. The accusations against one defendant were dropped after he died during the trial. The number of death sentences in Serbia has been lowered to seven by the Serbian High Court. Four of the remaining execution penalties were commuted by Regent Alexander, leaving only three death sentences in force. Four of the accused had confessed their roles in Sarajevo during the trial, and their final sentences were as follows:

Table: in Sarajevo and their final sentences

Serbia's "warning" to Austria-Hungary

Next the assassinations, Serbian Ambassadors to France Milenko Vesnić and Miroslav Spalajković released statements saying that Serbia had alerted Austria-Hungary about the imminent assassination. Serbia quickly denied issuing any warnings and knowledge of the plot. These denials were given by Prime Minister Pašić himself to Az Est on 7 July and the Paris Version of the New York Herald on 20 July. On 18 June, a telegram directed Serbia's Ambassador to Vienna, Jovan Jovanović, to alert Austria-Hungary that Serbia had cause to suspect Franz Ferdinand was being assassinated in Bosnia. Ambassador Jovanović seen with Austro-Hungarian Finance Minister Bilinski on 21 June.

Pai served as caretaker prime minister in the days immediately up to the killing since the Serbian government had momentarily fallen to a political alliance led by the Serbian military. The military preferred appointing Jovan Jovanović to Foreign Minister, and one might expect Jovanović's loyalties to be divided and his commands to be inadequately carried out as a result. Pašić, a survivor, evaded his bets against the numerous probable events and implications of the impending assassination by choosing a military loyalist to deliver the message and not including any specifics such as the conspirators' identities and weaponry.

Rade Malobabic

Rade Malobabi was the principal undercover operative for Serbian Military Intelligence against Austria-Hungary in 1914. During the conflict, his name appeared in Serbian records captured by Austria-Hungary. These records detail Malobabi's control over weaponry, munitions, and agents from Serbia into Austria-Hungary.

Black Hand

Another idea is that the Sarajevo attack was a "Black Hand" operation rather than a Serbian military intelligence operation. The "Black Hand" was a Serbian military club founded on 9 May 1911 by officers in the Army of the Kingdom of Serbia. It had its origins in the conspiracy group that assassinated the Serbian royal couple in May 1903, commanded by captain Dragutin Dimitrijević, also known as "Apis."

Since of the death of its President and the failure to substitute him, an inactive secretary, casualties, broken links between its three-person cells, and a lack of money, the "Black Hand" went dormant after Serbia's victory over Bulgaria in Macedonia in the Balkan Wars. By 1914, the "Black Hand" was no lengthier governed by its constitution but rather as a creation of Apis, the Chief of Serbian Military Intelligence. Its active ranks were primarily made up of Serbian officers loyal to Apis.

The Newspaper Clipping

During the trial, it was reported that the three Belgrade assassins attempted to place all guilt on themselves. Čabrinović stated the inspiration for the assassination of Franz Ferdinand originated from a newspaper clipping he received in the mail in late March announcing Ferdinand's intended visit to Sarajevo. He then showed Princip the newspaper clipping, and the next day they decided to assassinate Franz Ferdinand. Princip told the court that he had already read in German newspapers about Franz Ferdinand's impending visit. Princip then testified that he wrote an allegorical letter to Ilić around Easter (19 April) notifying him of assassinating Franz Ferdinand. Grabež said that he and Princip agreed to assassinate either Governor Potiorek or Franz Ferdinand around Easter and eventually settled on Franz Ferdinand. Under cross-examination, the defendants refused or were unable to provide details.

On 26 March, Mehmedbašić and Ilić had by now settled to assassinate Franz Ferdinand based on Belgrade's instructions, which came before the newspaper clipping and the three assassins' meetings in Belgrade.

Narodna Odbrana

Serbian Military Intelligence breached the Narodna Odbrana, using its underground tunnel to carry assassins and their weapons from Belgrade to Sarajevo, thanks to remnants of the "Black Hand." In the penultimate statement dealing with Sarajevo in the 5 June 1914 report by Leader of the Boža Milanović to Prime Minister Pašić, one can perceive the President's displeasure over the takeover of his organization. All of the agents have been warned by Boža that they should not receive anyone until he presents the password that Boža has given them.

Milan Ciganovic

Prime Minister Pašić was informed about the assassination plot early on. According to Education Minister Ljuba Jovanović, Pašić obtained the information early enough for the government to dispatch border guards to prevent the killers from crossing. The cabinet ministers' discussions will take place in late May, and the material will be released before then. Albertini found that Milan Ciganović was most likely the source of information. However, Bogičević offered a stronger argument.

His sinecure government employment, his protection by the Chief of Police, and Serbia's failure to arrest him are all circumstantial evidence against Ciganović. Austria-Hungary ordered that Serbia arrest both Major Vojislav Tankosić and Ciganović; however, Serbia only detained Tankosić and lied about Ciganović's whereabouts, Serbia's protection of Ciganović during the war, and the government's care for Ciganović after the war. Except for Ciganović, who testified against his companions at the trial, all of the Sarajevo conspirators under Serbian authority were tried at Salonika in 1917 on false charges.

Russian Military Attache's Office

According to Apis' confession to ordering Franz Ferdinand's killing, Russian Military Attaché Artamonov pledged Russia's protection from Austria-Hungary if Serbia was ever attacked. In an interview with Albertini, Artamonov denied his office's involvement in the killing while confirming support of the espionage network in Austro-Hungary. Artamonov claimed that he went on vacation to Italy, leaving Assistant Military Attaché Alexander Werchovsky in charge. Despite being in daily touch with Apis, he was unaware of Apis's participation until the war was over. According to Albertini, the officer's actions did not persuade him. Werchovsky acknowledged his office's involvement before going mute on the matter.

The assassination of the Austro-Hungarian Empire's heir and his wife shocked European royal houses, and there was originally a lot of sympathy for the Austrian cause. However, ordinary people were unconcerned about what had happened, and crowds in Vienna listened to music and drank wine as if nonentity had happened the night of the assassination. Within two days of the murder, Austria-Hungary and Germany recommended Serbia launch an investigation. Still, Slavko Gruic, Secretary-General of the Serbian Ministry of Foreign Affairs, responded that nothing had been done so far and that the situation did not interest the Serbian government. The Austrian Chargé d'Affaires in Belgrade and Gruic then had a heated exchange.

On 23 July 1914, Austria-Hungary submitted a formal letter to the government of Serbia after conducting a criminal inquiry, verifying that Germany would honour its military alliance and persuading the dubious Hungarian Count Tisza. Serbia was reminded in the letter of its commitment to uphold the Great Powers' decision in Bosnia-Herzegovina and maintain good neighbourly relations with Austria-Hungary. Furthermore, the letter included specific demands that Serbia should accept, such as the suppression of propaganda supporting the violent destruction of Austria-Hungary, the removal of those responsible from the Serbian soldierly, the closure of the Serbian nationalist group Narodna Odbrana, and the arrest of those involved in the assassination on Serbian soil. It further demanded that officials from the Austro-Hungarian Empire participate in the Serbian investigation into the assassination plot.

This letter became recognized as the July Ultimatum, and Austria-Hungary threatened to recall its ambassador from Serbia if Serbia did not accept all of the requests in whole within 48 hours. Serbia mobilized its army after receiving a telegram of support from Russia and responded to the letter by completely accepting point number 8, which demanded an end to weapon smuggling and the punishment of border officers who had assisted the assassins, as well as completely accepting point number 10, which requested Serbia report on the implementation of the required measures as they were completed. Instead, Serbia took, finessed, disingenuously responded, or respectfully rejected portions of the preamble and enumerated requests 1–7 and 9. Austria-Hungary published the deficiencies of Serbia's response. Austria and Hungary retaliated by severing diplomatic ties. According to research published in 2021, Franz Ferdinand's absence was essential in the failure of diplomacy and the escalation into war, as Ferdinand had been the most solid and successful proponent of peace in Vienna.

The next day, Serbian reservists on Danube tramp steamers crossed into Austro-Hungarian territory at Temes-Kubin, prompting Austro-Hungarian soldiers to fire warning shots into the air. This incident was initially reported to Emperor Franz-Joseph as "a significant skirmish," which was incorrect. On 28 July 1914, Austria-Hungary declared war on Serbia and mobilized the army that would meet the (already mobilized) Serbian Army. If either Triple Alliance armies activated, Russia and France were required to mobilize their soldiers under the 1892 Secret Treaty. On 29 July, Russia partially mobilized along the Austrian border, and on 30 July, Russia authorized a general mobilization. The universal rally of Russia triggered the total mobilization of the Austro-Hungarian and German armies. Except for Italy, all of the Great Powers had quickly picked sides and entered the war.