Saint Cybi, or Cuby, was a 6th-century Cornish bishop, saint, and, briefly, king, who worked largely in Cornwall and North Wales: his biography is recorded in two slightly variant medieval 'lives'.

Saint Cyngar was a 5th-century Welsh Saint. He is the Patron Saint of Llangefni, Anglesey, in Wales, and a founding member of St. Cybi's Monastery at Holyhead, Anglesey.