Petro II Orseolo was the Doge of Venice from 991 to 1009.
He began the period of eastern expansion of Venice that lasted for the better part of 500 years.
Following repeated complaints by the Dalmatian city-states in 997, the Venetian fleet under Orseolo attacked the Slavic pirates of Narenta on the Ascension Day in 998 and finally defeated them. Pietro then took the title of Dux Dalmatianorum (Duke of Dalmatia), associating it with his son.
The date of his victory became that of the Festa della Sensa, the Ascension Festival, the oldest festival in Venice. It was commemorated by the Doge and the bishop of Olivolo going past the Lido and blessing the waters, invoking good fortune for the Venetian navy.
