Mark of Cornwall

Mark of Cornwall (Latin: Marcus, Cornish: Margh, Welsh: March or Marchell, Breton: Marc'h) was a sixth-century King of Kernow (Cornwall), possibly identical with King Conomor. He is best known for his appearance in Arthurian legend as the uncle of Tristan and the husband of Iseult who engages with Tristan in a secret liaison, giving Mark the epithet "Cuckold King".