Ladislaus I or Ladislas I, also Saint Ladislaus or Saint Ladislas (c. 1040 – 29 July 1095) is King of Hungary from 1077 and King of Croatia from 1091.
He is the second son of King Béla I of Hungary who dies in 1063.
He and his elder brother, Géza conclude a treaty with their cousin, Solomon: they acknowledge Solomon's reign in exchange for receiving their father's former duchy which includes one third of the Kingdom of Hungary.
Ladislaus is an influential advisor of his brother who is proclaimed king against their cousin in 1074.
Ladislaus succeeds his brother in 1077, but Solomon is able to contest him from two fortresses—Moson and Pressburg (Bratislava, Slovakia)—in the western regions, for King Henry IV of Germany supports Solomon.
Ladislaus makes an alliance with the German monarch's opponents during the first phase of the Investiture Controversy.
Solomon abdicates and acknowledges Ladislaus's reign in 1081, but he conspires against the king and is imprisoned.
Ladislaus sets his dethroned cousin free on the occasion of the canonization of the first saints in Hungary—including, his distant relatives, King Stephen I and Duke Emeric—in 1085.
Following a series of civil wars, Ladislaus strengthens public safety by introducing severe legislation.
His occupation of Croatia in 1091 marks the beginning of a period of expansion of the medieval Kingdom of Hungary.
His victories over the Pechenegs and Cumans ensure the security of his kingdom's eastern borders for about 150 years.
He is canonized on 29 June 1192.
His legends depict him as a pious knight-king.
He is a popular saint in Hungary and in the neighboring countries where many churches are dedicated to him.
