During the Ottoman-Venetian War of 1570-1573, he supported the rebellion of Emmanuel Mormoris in Ottoman-ruled Epirus. As such, Lantzas made preparatory skirmishes and raided Turkish ships in the regions of Lepanto and Preveza. He also attacked inland regions and penetrated as far as Delvinë. At the end of the war (1573), he was appointed governor of the coastal town of Parga, opposite of Corfu, by the Venetians.