His Majesty Sri Sultan Hamengkubuwono X (also spelled as Hamengkubuwana X, often abbreviated as HB X) (born BRM Herjuno Darpito, 2 April 1946 in Yogyakarta) is the Sultan of the historic Yogyakarta Sultanate in Indonesia, and is currently also the Governor of the modern Yogyakarta Special Region (Daerah Istimewa Yogyakarta).