Ladislaus I of Hungary

Ladislaus was the second son of King Béla I, born in 1040, and spent his early years sharing power: after his father's death in 1063, he and his brother Géza accepted their cousin Solomon as king in exchange for a third of the realm. A decade of cooperation ended when the brothers turned on Solomon in the early 1070s, Géza took the throne in 1074, and Ladislaus became his closest adviser. When Géza died in 1077, Ladislaus claimed the crown, fought Solomon with backing from the pope's enemies in the Investiture Controversy, and finally forced his cousin to abdicate in 1081 - then jailed him when he plotted a comeback. He spent the next years restoring order through harsh laws that punished theft and property violation with death or mutilation, canonized Hungary's first saints in 1085 (freeing Solomon during the ceremony), and conquered nearly all of Croatia by 1091. His campaigns against the Pechenegs and Cumans secured Hungary's eastern frontier for a century and a half, though his final years brought conflict with Rome over who controlled Croatia. He died in 1095, and Pope Celestine III canonized him in 1192 as the embodiment of the chivalric ideal.