The cathedral was erected between 1131 and 1240 in the Norman architectural style, the island of Sicily having been conquered by the Normans in 1091. According to tradition, the building was erected after a vow made to the Holy Saviour by the King of Sicily, Roger II, after he escaped from a storm to land on the city's beach. The building has a fortress-like character and, seen from a distance, it dominates the skyline of the surrounding medieval town. It made a powerful statement of the Norman presence.