Piotr (I) of the coat of arms of Półkozice (died around 1239[1]) was bishop of Płock around the years 1232–1239.
In 1232, he was elected a bishop of Płock by the cathedral chapter, according to Jan Dlugosz half of them[3] supported him.
Thanks to his support, he received a commission from Pope Gregory IX and probably even in the year of the election he appeared as a bishop.
He witnessed on the divisional document between Mazovia and Kujawy between the older sons of Prince Konrad - Bolesław I and Kazimierz I in 1238.
In 1239, on the part of the Masovian dukes, Konrad I and Bolesław I obtained exemption privileges for the Płock Church.