The Revolt of the Czechoslovak Legion in May 1918, radically changed the situation in Siberia. On May 25 legionaries captured Mariinsk, the next day Chelyabinsk and Novonikolaevsk. On May 28 A. Grishin-Almazov came to Novonikolaevsk and proclaimed himself commander of all troops in the Western Siberian Military District. At that time most members of PGAS (including Derber and Krakovetsky) were in Vladivostok; hence, it was necessary to create a structure of government without them. On May 30 a meeting took place in Novonikolaevsk, the so-called "Council of representatives of PGAS", which organized the provisional Western Siberian Commissariat.