Kentigern (called 'Mungo,' the dear one) was the son of the British princess Teneu, who had been cast off a cliff at Aberlady Bay by her father when found pregnant unmarried. Miraculously surviving, she was rescued and gave birth to her son at Culross in Fife, where the monk St. Serf raised him and gave him the name Mungo.
Mungo settled at Glasgow on the Molendinar Burn around 540, founded a monastic settlement, and was consecrated bishop of Strathclyde — the British kingdom that then covered south-west Scotland and north-west England. He was driven into exile in Wales by Arthurian-era political upheavals, founded the monastery of Llanelwy (later St Asaph's), and was eventually invited back to Glasgow by King Rhydderch the Generous.
The four traditional miracles of Kentigern — preserved in the Glasgow coat of arms with the rhyme 'Here's the bird that never flew, here's the tree that never grew, here's the bell that never rang, here's the fish that never swam' — are: the bird he raised from the dead, the frozen branch that gave fire by his prayer, the bell brought from Rome, and the salmon with the queen's ring in its mouth (which he caught to save the queen from her husband's suspicion). Glasgow Cathedral is built over his tomb.