Dogado
One of his first acts as doge was the blinding and expulsion of the bishop of Castello, accused of simony. In June 960, he reconvened the popular assembly and had them approve of a law prohibiting the slave trade.
For political reasons, Pietro repudiated his first wife, Joan, forcing her into the convent of Santa Zaccaria. He had had two children through her: his son Vitale was later elected doge and his daughter was married to Tribuno Memmo, a future doge. In 966, Pietro remarried to the Lombard Waldrada, daughter of Hubert, Duke of Spoleto, and a relative of the Emperor Otto I. As a relative also of the king of Italy, Waldrada brought him a large dowry including the possession of Treviso, Friuli, and Ferrara.
On 2 December 967, Pietro obtained from the emperor the renewal of a series of commercial privileges, for the Venetians in general, but also for himself and his family in particular. While this tightened the ties with the empire of the West, it greatly angered the emperor of the East, John I. John threatened war if the Venetians would not stop contrabanding with the Saracens against whom John was then battling fiercely on multiple fronts. In 971, Pietro had to consent to end the trade with the Moslems.
Read more about this topic: Pietro IV Candiano