Saint Melaine (Latin: Melanius or Mellanus; Cornish: Melan; Welsh: Mellon) was a 6th-century Bishop of Rennes in Brittany (now in France).
Melaine grew up at Plaz in Brain, near Redon. He was a pious child, often being punished for spending too long at his prayers. He became a monk and then abbot. He was nominated the successor to Saint Amand of Rennes as Bishop of Rennes. During his rule, Clovis took over the area and Melaine became his trusted advisor. He opposed immigration from Britain and attended the First Council of Orléans in 511. He died at Plaz before 549 and was buried in the Abbey Church of Notre-Dame en Saint-Mélaine in Rennes.
Traditions recounted by Baring-Gould state that on the death of Amand, he was compelled by the local population to become the next Bishop, accepting the role with great reluctance; that he performed many miracles and put an end to heathen practices; and that following his death at La Vilaine, his body was placed on a boat which then returned to Rennes against the current without the assistance of rowers or sails.
Melaine quickly became revered as a saint, especially after the wooden tower above his grave burnt down and his tomb miraculously survived. He has three feast days: 6 November (death), 6 January (burial) and 11 October (translation).
In Wales, his feast is celebrated locally on 10 October rather than 11 October at St Mellons, in modern-day Cardiff, though there is ambiguity over whether Melaine is the Saint 'Mellonius' said to have been born there.