Jewish migration into what is now Israel increased after Britain took Palestine from the Ottoman Empire in 1917 and issued a pledge to encourage the "establishment of Palestine as a home for the Jewish people." This pledge is known as the:

Jewish migration into what is now Israel increased after Britain took Palestine from the Ottoman Empire in 1917 and issued a pledge to encourage the "establishment of Palestine as a home for the Jewish people." This pledge is known as the Balfour Declaration.

Explanation:

The Balfour Declaration of 1917 (dated November 2, 1917) was a secret, formal, political statement made by British Foreign Secretary Arthur James Balfour, in which he informed Lord Walter Rothschild, the leader of the Jewish community in England, that the British Government supported the proposal to establish a Jewish homeland in Palestine; however, it also provided that this would not infringe on the civil and religious rights of pre-existing non-Jewish communities or the rights and political status of Jews in any other country. Palestine was still formally part of the Ottoman Empire in 1917, but after World War I became an area managed by Britain on behalf of the League of Nations.

The Balfour Declaration, which was intended to win all the Jews of the world for the cause of the entente in the then World War I, led, among other things, to the establishment of the British Palestine Mandate in 1920 and became, after World War II, one of the cornerstones of British Palestinian politics.