The people of the Biak Islands (off the northern coast of western New Guinea) speak one language, known as Biak, Numfor, or Biak-Numfor. Prior to European colonisation in the early 1900s, they were nominal vassals of the Tidore Sultanate. They are particularly well know for having being at the centre of the Koreri movement, a syncretic religion centering on the culture-hero Manarmakeri.