A Czech duke from 1055, and a member of the Přemyslids. He ruled with an iron fist and temporarily stripped the Moravians of their rights and reigned over the whole of the Czech lands. He supported the church, founding a chapter house in Litoměřice (1057) and in 1060 he embarked on a major reconstruction of the St. Vitus church at Prague Castle. He evicted the Slav monks from the monastery at Sázava and replaced the Slav liturgy with the Latin version. He attempted to gain the title of king from the Pope but was unsuccessful.