In 1925 the Majles deposed the absentee monarch, and a constituent assembly elected Reza Khan as shah, vesting sovereignty in the new Pahlavi dynasty. After his coronation in April 1926, Reza Shah continued the radical reforms he had embarked on while prime minister. He broke the power of the tribes, which had been a turbulent element in the nation, disarming and partly settling them. In 1928 he put an end to the one-sided agreements and treaties with foreign powers, abolishing all special privileges. He built the Trans-Iranian Railway and started branch lines toward the principal cities (1927–38).
