The two maritime powers had long been leading commercial powers with ties to Constantinople that had nurtured their growth during the Dark Ages. Their rivalry over trade with the Levant had generated a number of wars. Genoa, having suffered previous defeats at the hands of the Venetians, had emerged from submission to the Visconti tyrants of Milan during the fourteenth century, although it had also been severely weakened by the Black Death of 1348 which took a toll of 40,000 on the city. Venice had dismembered the Byzantine Empire in 1204 and gradually taken over land on the Adriatic — bringing it into conflict with Hungary, and land within Italy — generating a rivalry with Padua.