Unification or Death unofficially known as the Black Hand (Црна рука, Crna ruka), was a secret military society

Secret society

A secret society is a club or organization whose activities and inner functioning are concealed from non-members. The society may or may not attempt to conceal its existence. The term usually excludes covert groups, such as intelligence agencies or guerrilla insurgencies, which hide their...

 formed by members of the Serbian army

Serbian Army

-Objectives:The Serbian Army is responsible for:* deterring armed threats* defending Serbia's territory* participation in peacekeeping operations* providing humanitarian aid and disaster relief-Personnel:...

 in the Kingdom of Serbia

Kingdom of Serbia

The Kingdom of Serbia was created when Prince Milan Obrenović, ruler of the Principality of Serbia, was crowned King in 1882. The Principality of Serbia was ruled by the Karađorđevic dynasty from 1817 onwards . The Principality, suzerain to the Porte, had expelled all Ottoman troops by 1867, de...

, which was founded on September 6, 1901. It was intent on uniting all of the territories containing significant Serb populations annexed by Austria-Hungary

Austria-Hungary

Austria-Hungary , more formally known as the Kingdoms and Lands Represented in the Imperial Council and the Lands of the Holy Hungarian Crown of Saint Stephen, was a constitutional monarchic union between the crowns of the Austrian Empire and the Kingdom of Hungary in...

. Through its purported connections to the June 1914, assassination

Assassination of Archduke Franz Ferdinand of Austria

On 28 June 1914, Archduke Franz Ferdinand of Austria, heir presumptive to the Austro-Hungarian throne, and his wife, Sophie, Duchess of Hohenberg, were shot dead in Sarajevo, by Gavrilo Princip, one of a group of six Bosnian Serb assassins coordinated by Danilo Ilić...

 in Sarajevo

Sarajevo

Sarajevo |Bosnia]], surrounded by the Dinaric Alps and situated along the Miljacka River in the heart of Southeastern Europe and the Balkans....

 of Franz Ferdinand, Archduke of Austria, the Black Hand may have been one of the principal catalysts to the start

Causes of World War I

The causes of World War I, which began in central Europe in July 1914, included many intertwined factors, such as the conflicts and hostility of the four decades leading up to the war. Militarism, alliances, imperialism, and nationalism played major roles in the conflict as well...

 of World War I

World War I

World War I , which was predominantly called the World War or the Great War from its occurrence until 1939, and the First World War or World War I thereafter, was a major war centred in Europe that began on 28 July 1914 and lasted until 11 November 1918...

.
The Black Hand was founded on September 6, 1901.