Complex sentence: Established on 28 April 1920 as the Azerbaijan SSR, from 12 March 1922 to 5 December 1936, it was part of the Transcaucasian SFSR together with the Armenian SSR and the Georgian SSR.
Split into simpler sentences: Established on 28 April 1920 as the Azerbaijan SSR. From 12 March 1922 to 5 December 1936, it was part of the Transcaucasian SFSR together with the Armenian SSR and the Georgian SSR.