Giovanni Luigi Fiesco, count of Lavagna, a conspirator of Genoa, born there about 1524, drowned Jan. 2, 1547. Wealthy, accomplished, and of high rank, he evinced from his earliest youth an insatiable lust of power, and succeeded in making himself popular with the common people. Andrea Doria was at that time the ruler of Genoa, and although Fiesco was not so much opposed to Andrea as personally exasperated against his nephew Gian-nettino (who was allowed a precedence of rank which was due to himself), he instigated, in concert with Calcagno, Verrina, Sacco, and other discontented politicians, a conspiracy with the view of overthrowing the existing government. The rebellion broke out in the night of Jan. 1-2, 1547. Giannettino Doria was killed, but his uncle the doge escaped. Fiesco himself fell into the water and was drowned while going on board a galley in the port of Genoa,and his death put an end to the outbreak. The life of his widow was spared, but two of his brothers, Geronimo and Ottoboni, were put to death, and the other leaders of the revolt had their property confiscated and were banished by the doge, although an amnesty had been originally granted to them by the senate.

An account of the conspiracy of Fiesco was written in 1629 by Augustino Mascardi, and after him by Cardinal de Retz. It also forms the subject of Schiller's tragedy, Fiesco.