Stanislaus of Masovia, Stanis?aw mazowiecki was a Polish duke of Masovia. Son of Konrad III Rudy. Until 1518 Masovia was under regency of his mother Anna Radziwi??, afterwards he became its ruler till his death in 1524.
He was born on 17 May 1501.
In 1523 he started negotiation about marriage to Jadwiga Jagiellonka, daughter of Zygmunt I, king of Poland.
He died on 8 August 1524, probably shortly before Noon. Stanislaus was buried at St. John's Archcathedral in Warsaw.