The Cathedral of Palermo is a magnificent religious building built in the 12th century and dedicated to Vergine Assunta. The Catholic sanctuary was built in Norman times on what had been a Saracen mosque and even earlier a Christian Basilica. Today, even after many other alterations, several architectural styles characterise its appearance: the arcade of the main façade is in Catalan Gothic style and dates back to the 15th century. The dome is late Baroque, the interior is neoclassical in the Latin cross style and the oldest part, the apse, has Arab-Norman decorations. The Cathedral of Palermo holds the mortal remains of Sicilian royals, including those of the founder of the Kingdom of Sicily Roger II and the Holy Roman Emperor Frederick II, and those of Santa Rosalia, the city’s patron saint. Worth visiting are also the crypt and the treasure.