Ladislaus was born in exile in Poland to King Béla I of Hungary, a member of the Árpád dynasty. Returning to Hungary as a young man, he proved himself an unusually able military commander; after the death of his brother Géza I, he was elected king in 1077 over the protests of the dispossessed claimant Solomon.
His seventeen-year reign reorganised Hungary after the disasters of the previous decade: codifying the kingdom's law, defending its borders against the Pechenegs, Cumans, and Bohemians, conquering Croatia and Dalmatia, founding the diocese of Zagreb, and reasserting the religious settlement of his sainted predecessor Stephen. He sided with Pope Gregory VII in the Investiture Controversy against Henry IV.
He died at Nyitra in 1095 while preparing for the First Crusade, which he had been invited to lead. Canonised by Celestine III in 1192. The vast popular devotion to Ladislaus shaped much of medieval Hungarian visual culture; cycles of his life were painted on parish-church walls across the kingdom in the 14th–15th centuries.

