The Moscow uprising of 1648 (Russian: Соляной бунт, Московское восстание 1648), sometimes known as the salt riot, started because of the government's replacement of different taxes with a universal salt tax for the purpose of replenishing the state treasury after the Time of Troubles. This drove up the price of salt, leading to violent riots in the streets of Moscow. The riot was an early challenge to the reign of Alexei I, eventually resulting in the exile of Alexei's advisor Boris Morozov.