*Peter I (r. 1682 - 1725), byname "Peter the Great." First tsar to be proclaimed emperor (1721). The succession law of 1722 provides that a tsar name his successor. | *Peter I (r. 1682 - 1725), byname "Peter the Great." First tsar to be proclaimed emperor (1721). The succession law of 1722 provides that a tsar name his successor. |