Sophia Alekseyevna (sô´fyə əlyĬksyā´yəvnə), 1657–1704, regent of Russia (1682–89); daughter of Czar Alexis by his first wife and sister of Czar Feodor III. Supported by the streltsi (semimilitary formations in Moscow), she seized power shortly after Feodor's death (1682) and was proclaimed regent during the minority of her retarded brother, Ivan V, and of her half-brother, Peter I (Peter the Great), who reigned jointly. She brutally eliminated her opponents and ruled autocratically with her lover Vasily V. Gallitzin (see under Gallitzin). Sophia wished to be crowned czarina in her own right, but she lacked sufficient support among the nobility and clergy. Gallitzin's two unsuccessful campaigns against the khan of Crimea helped undermine Sophia's power. When it was rumored that she intended to kill Peter and proclaim herself sole ruler, Peter summoned the nobles and his loyal guards, overthrew the regency, deposed Ivan, exiled Gallitzin, and had Sophia confined in a convent. After an attempted revolt of the streltsi, Peter forced her (1689) to take the veil.