Ostasio I da Polenta
Ostasio I da Polenta (died 1346) made himself lord of Ravenna by murder. The son of Bernardino da Polenta, lord of Cervia, in September 1322, with his cousin Guido Novello away serving at Bologna, he seized Ravenna and killed Archbishop Rinaldo da Polenta.
In 1326 he killed his uncle Bannino, who held Cervia, and took that lordship as well. A patron of letters, he had Giovanni Boccaccio at his court in 1345–1346.
Pope Benedict XII gave his rule legal standing by naming him papal vicar, but Ostasio died that November, allegedly murdered by his son Bernardino, who succeeded him.