Aleksey Mikhailovich (; – ) was the Tsar of Russia during some of the most eventful decades of the mid-17th century. His reign saw the Russian invasion of Polish–Lithuanian Commonwealth and war with powerful Sweden during the Deluge, the Raskol schism in the Russian Orthodox Church, and the Cossack revolt of Stenka Razin. On the eve of his death in 1676, the Tsardom of Russia spanned almost .