Unlike the small numbers of Jews who had returned to Palestine over the centu- ( . the late 19th and early 20th century immigrants thoroughly transformed the ; lewish community in Palestine (the “Old Yishuv") and profoundly affected the political status of the region. With the sponsorship of Baron Edmund de Rothschild in Paris agricultural settlements based on private land ownership (mosbavim) were the work of the first wave of immigrants (aliya, or “going up") in 1882. Members of the second aliya (1904-1914) developed cooperative agricultural settlements, or kibbutzim. Far from a mere klatch of disaffected East European youth, die leadership of the second aliya shared the socialist principles, sense of urgency, and nationalist sentiment needed to keep the Zionist ideals alive. Two distinct strands of Zionism evolved in the Yishuv: the mainstream Labor movement under David Ben-Gurion. and the more militant, nationalistic, and anti-British Revisionist movement under Ze’ev Jabotinsky and Menahem Begin.

During World War I, the British government, at war with pro-German Turkey, conducted secret and separate negotiations with both the Arabs and the Zionists to enlist their help. To obtain Arab support, Britain pledged in 1915-16 correspondence between Sharif Hussein of Mecca (of the Hashemite family, and a descendent of Muhammad) and British High Commissioner in Egypt Sir Henry McMahon to back “the independence of the Arabs” in exchange for an Arab declaration of war against Turkey. The Arab revolt started in June 1916. At the same time, Britain sought political support from Jews worldwide by offering sympathy to the Zionist movement. The November 1917 Balfour Declaration stated that Britain viewed “with favour the establishment in Palestine of a national home for the Jewish people, it being clearly understood that nothing shall be done which may prejudice the civil and religious rights of existing non-Jewish communities in Palestine.” Many Arabs were outraged, and Hussein’s suspicions of his British allies grew. The vague wording in the Balfour Declaration and the ambiguity of the boundaries agreed upon in the McMahon-Hussein correspondence only complicated the situation.