The Haganah (Defense) Organization (short for “The Hebrew Defense Organization in Eretz Israel”) was established in 1920 and was the largest military body in the Jewish Yeshuv during the British Mandate. When the mandate ended and the State of Israel was declared, it became the Israel Defense Force (IDF).
The main objective of the Haganah was to safeguard the life and property of every Jew living in Eretz Israel. Its troops were trained clandestinely, preparing them for the struggles of the day with the Arabs and (at times) the British, as well as for the purpose of serving as a defensive shield for the future Jewish State. To that end, they established units, battalions, divisions, corps and services like those of an active army, which proved themselves in times of emergency from 1920-1947 and especially in the first few months of 1948, during the War of Independence, until the Haganah became the IDF.
In addition, the Haganah took it upon itself to expand the area of security settlements throughout Eretz Israel, to determine the future borders of the Jewish State. The organization played an especially memorable role in the “Wall and Tower” operation during which more than 50 fortified towns were established, as well as in the pioneering settlement of the Negev Desert, which led to this large desolate region begin included in the map of the Jewish State declared by U.N. resolution of November 29, 1947.
The Haganah was also responsible for the illegal immigration to Eretz Israel when the British Mandate locked its gates. The Haganah brought in some 100 ships carrying 90,000 immigrants. Thousands of others arrived by land from countries in the Middle East. There was even illegal immigration via air – 150 immigrants came on three flights from Iraq and Italy.
The Haganah trained thousands of commanding officers at all levels and they formed the organization’s command infrastructure as well as that of the IDF for decades afterward.