The prince (French: Prince de Monaco) or princess of Monaco (French: princesse de Monaco) is the monarch and head of state of the Principality of Monaco. All reigning princes and princesses have taken the name of the House of Grimaldi, although some have belonged to other families (Goyon de Matignon or Polignac) in the male line. When Prince Rainier III died in 2005, he was Europe's longest reigning monarch. The Grimaldi family, which has ruled Monaco for eight centuries, is Europe's longest-ruling royal family. The presently reigning prince is Albert II, who ascended in April 2005.