The Croatian–Venetian wars were a series of periodical, punctuated medieval conflicts and naval campaigns waged for control of the northeastern coast of the Adriatic Sea between the City-state (later the Republic) of Venice and the Principality of Croatia (later turned to the Kingdom of Croatia, as well as the Kingdom of Croatia in personal union with Hungary), at times allied with neighbouring territories – the Principality of the Narentines and Zahumlje in the south and Istrian peninsula (then partially ruled by the German feudal families) in the north. First struggles occurred at the very beginning of the existence of two conflict parties (7th and 8th century), they intensified in the 9th century, lessened during the 10th century, but intensified again since the beginning of the 11th ce