The Jewish Legion was the name for five battalions of Jewish volunteers established as the British Army

British Army

The British Army is the land warfare branch of Her Majesty's Armed Forces in the United Kingdom. It came into being with the unification of the Kingdom of England and Scotland into the Kingdom of Great Britain in 1707. The new British Army incorporated Regiments that had already existed in England...

's 38th through 42nd (Service) Battalions of the Royal Fusiliers. The initial unit, known as the Zion Mule Corps, was formed in 1914-1915 during 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...

, when Britain

United Kingdom of Great Britain and Ireland

The United Kingdom of Great Britain and Ireland was the formal name of the United Kingdom during the period when what is now the Republic of Ireland formed a part of it....

 was at war against the Ottoman Empire

Ottoman Empire

The Ottoman EmpireIt was usually referred to as the "Ottoman Empire", the "Turkish Empire", the "Ottoman Caliphate" or more commonly "Turkey" by its contemporaries...

, as Zionists

Zionism

Zionism is a Jewish political movement that, in its broadest sense, has supported the self-determination of the Jewish people in a sovereign Jewish national homeland. Since the establishment of the State of Israel, the Zionist movement continues primarily to advocate on behalf of the Jewish state...

 around the world saw an opportunity to promote the idea of a Jewish National Homeland.

In December 1914, Zeev Jabotinsky and Joseph Trumpeldor

Joseph Trumpeldor

Joseph Trumpeldor , was an early Zionist activist. He helped organize the Zion Mule Corps and bring Jewish immigrants to the Land of Israel. Trumpeldor died defending the settlement of Tel Hai in 1920 and subsequently became a Zionist national hero...

 raised the idea of the formation of a Jewish unit that would participate in the British military effort to conquer Palestine

Palestine

Palestine is a conventional name, among others, used to describe the geographic region between the Mediterranean Sea and the Jordan River, and various adjoining lands....

 from the Ottoman Empire

Ottoman Empire

The Ottoman EmpireIt was usually referred to as the "Ottoman Empire", the "Turkish Empire", the "Ottoman Caliphate" or more commonly "Turkey" by its contemporaries...

, and by the end of March 1915, 500 Jewish volunteers from the Jews in Egypt who had been deported there by the Ottomans had started training.