He died in 576. Constantine was a king of Cornwall, the son of Padeon, whose conversion probably dates from a confrontation with St. Petroc who was sheltering a stag which had taken refuge with him.
Constantine married a princess from Brittany who died shortly after the marriage and the King was so desolated that he left his kingdom and sought sanctuary, first at S. David’s monastery at Menevia and then in Ireland at Rathin, made famous by St. Carthage and Mochuda. He arrived at Rathin unannounced and was set to work in the granary, grinding corn in a stone quern. One day he was heard by one of the monks laughing and saying to himself, “Is this really Constantine, King of Cornwall, who wore a helmet and bore a shield, working this handmill? It is the same, and yet it is not”.
This conversation was reported to the abbot who took him into the community and after a while he was ordained priest. He had spent seven years at the abbey before he was recognised and by now he was quite an old man, but he desired to visit Iona and set off with the blessing of the abbot. St. Columba received him kindly and sent him on to Sr. Kentigern, whom he may have met when he was at Menevia. While visiting Glasgow he stayed for some time with St. Mirren at Paisley and the two became great friends so that Constantine decided to build himself a monastery nearby at Govan by the river. It is interesting that the ruined church of St. Constantine, on the shore of the Bay that bears his name, has the parish of St Merryn adjoining it and the font in St Merryn’s Church comes from St Constantine’s.
After St. Constantine had founded his monastery at Govan he still felt impelled to preach the Faith of Christ to the heathen and he went to Kintyre with a party of his monks. There, by Campbeltown Loch a party of robbers came upon him and hacked him and his one attendant to pieces. The ruins of a church at Kilchouslan are supposed to mark the spot where the first of the martyrs of Scotland was attacked and left to die, bleeding to death from a severed arm. His brethren found him and received his blessing before he died. They took his body back to Govan and buried him in the church that has his name. His sarcophagus was discovered in 1855 and has been restored to the church which keeps his festival on March 11th.
Troparion of St Constantine Tone 5
Grieving at the loss of thy young spouse,/ thou didst renounce the world, O Martyr Constantine,/ but seeing thy humility God called thee to leave thy solitude and serve Him as a priest./ Following thy example,/ we pray for grace to see that we must serve God as He wills/ and not as we desire,/ that we may be found worthy of His great mercy.
Kontakion of St Constantine Tone 4
Thou wast born to be King of Cornwall,/ O Martyr Constantine,/ and who could have foreseen that thou wouldst become the first hieromartyr of Scotland./ As we sing thy praises, O Saint,/ we acknowledge the folly of preferring human plans to the will of our God.