Romanus I (Romanus Lecapenus), d. 948, Byzantine emperor (920–44). An admiral, he usurped the throne during the minority of his son-in-law, Constantine VII. He defended Constantinople against the Bulgars under Simeon I and in 927 made peace with Simeon's son. He also tried unsuccessfully to protect peasant and military holdings from absorption into the estates of the great landowners. In 944, Romanus was overthrown by his two surviving sons, who were in turn overthown by Constantine VII.