Olaf II of Norway, also known as Saint Olaf, was a king who ruled from 1015 to 1028. He is best known for his efforts to convert Norway to Christianity and for unifying the country under a single monarchy. His reign was marked by battles against rival factions and the establishment of a more centralized government. After his death in battle in 1030, Olaf was canonized as a saint by the Catholic Church. His legacy includes the promotion of Christianity in Norway and the establishment of Nidaros Cathedral in Trondheim, which became a significant pilgrimage site in medieval Europe.