Mossad Le'aliyah Bet

The Mossad LeAliyah Bet (Hebrew: המוסד לעלייה ב'‎, lit. Institution for Immigration B) was a branch of the Haganah in the British Mandate of Palestine, and later the State of Israel that operated to facilitate Jewish immigration to British Palestine (later Israel). During the Mandate period, it was facilitating illegal immigration in violation of governmental British restrictions. It operated from 1938 until four years after the founding of the State of Israel in 1952. It was funded directly by the American Jewish Joint Distribution Committee (the JDC), and was not subject to the control of the Jewish Agency who operated their own Aliyah department headed by Yitzhak Rafael.

The Yishuv referred to legal immigration as "Aliyah Alef" (Alef is also the first letter of the Hebrew alphabet, corresponding to the Latin A), whilst clandestine immigration was referred to as "Aliyah Bet" (Bet is the second letter, corresponding to the Latin B).

In late 1938, due to domestic pressure in Palestine relating to local objections to Zionist immigration waves, the British government announced in (what became known as) the 1939 White Paper that it was to reduce Jewish migration to Palestine, and at that point the main body of Zionism decided to cease conforming with British regulations.

Even though the Mossad LeAliyah Bet was officially founded on 29 April 1939, it had begun operating during 1938. Headed by Shaul Avigur, the Mossad LeAliyah Bet was founded on the basis of the Ha'apala movement. Its activity was initially centred in Athens and later on its centre moved to Paris. The movement's leadership was drawn from both revisionist and mainstream Zionist activists. Avigur was followed at the helm of the organisation by Meir Sapir.

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