As stated in the introduction to the causes section of this Wikibook, the assassination of Archduke Franz Ferdinand of Austria was an event which led directly to declarations of war starting World War I.
The assassination was carried out by a group of six assassins, who intended to end the Austro-Hungarian Empire's control of some of it's southern provinces.
Danilo Ilić, who co-ordinated the assassination, discussed the idea of using violent direct action to achieve his goals in late 1913.
Originally Ilić's plan was to kill the governor of the region, although on March 26, 1914, he changed his intentions, and decided to plan an assassination of Franz Ferdinand.
In April Ilić persuaded Vaso Čubrilović and Cvjetko Popović to assist in the plot to assassinate the archduke.
In addition, Gavrilo Princip, Trifun Grabež and Nedjelko Čabrinović, the other individuals involved in the assassination, became involved in the plot at a similar time, after approaching others stating their wish to participate in an assassination.
Milan Ciganović, who had access to weapons and was a former guerrilla fighter agreed in April 1914 with Princip, Grabež and Čabrinović to provide the assassins with the weapons required to carry out the assassination.
Due to a delay, the weapons were only delivered on May 26.
Ciganović provided the assassins with training, suicide pills and money, in addition to six hand grenades and four automatic pistols with ammunition.
On May 28, just two days after the delivery of the weapons, Princip, Grabež, and Čabrinović left Belgrade by boat.
In the Sava River, the group traveled to Šabac, where they assumed the identities of custom officials.
With this new identity, the group took the train to Loznica, a town that was on the border between Serbia and the Austro-Hungarian Empire.