Stanislaus was born at Szczepanów in southern Poland, educated at the cathedral school of Kraków and probably at Liège or Paris, and was consecrated Bishop of Kraków in 1072. His episcopate coincided with the reign of King Bolesław II 'the Bold,' whose increasingly tyrannical conduct — the kidnapping of a nobleman's wife is the episode most often cited — led the bishop to formal excommunication of the king.
On April 11, 1079, as Stanislaus celebrated Mass at the church of St. Michael on the Skałka (the Rock) outside Kraków, Bolesław's soldiers refused to lay hands on him; the king himself entered the church and killed the bishop at the altar. The body was dismembered and thrown into a pool. Tradition records that four eagles guarded the pieces, that the parts miraculously rejoined when collected, and that the king fled into Hungarian exile and died penitent at the Benedictine abbey of Osjak in Carinthia.
Stanislaus was canonized in 1253 — the first Polish saint elevated by formal papal canonization — and became the heavenly patron of the Polish nation. His shrine at Wawel Cathedral in Kraków is the spiritual center of Polish Catholicism, and Karol Wojtyła was Archbishop of Kraków and his successor in the see of Stanislaus before becoming John Paul II.