The Hagana organization was founded in June 1920, and the first few months were tumultuous in Palestine.
The Hagana was established in June, 1920, during some of the country's most turbulent months. Yosef Trumpeldor, together with 6 of his men were killed during the Tel-Hai battle in March 1920. In addition, during the Arab riots of 1920 it became evident that the Yishuv could not rely on the British to defend them.
These events resulted in an urgent need to establish a national, independent, underground Jewish defense force.
Hashomer Council dismantled the organization (May-June, 1920), and transferred all defense responsibilities to the largest existing labor party, Achdut Haavoda (the political party seceded from Mapai, the main Labor Party). Responsibility for defense was accepted by the party during the Sea of Galilee convention, 13-15.6.1920.
The resolutions of the convention were: Achdut Haavoda acknowledged the importance of the historical responsibility granted to it by Hashomer, and committed to the participation of dedicated and alert workers in the national popular Defense organization, and to the creation of a police force. The initial Hagana acting committee would include members of Hashomer's last acting committee, including Eliyahu Golomb.
Based on these resolutions, the Hagana was established in 15.6.20.