Kentigern, known as Mungo, was an apostle of the Scottish Kingdom of Strathclyde in the late 6th century, and the founder and patron saint of the city of Glasgow.

The Life of Saint Mungo was written by the monastic hagiographer Jocelyn of Furness in about 1185. Jocelin states that he rewrote the 'life' from an earlier Glasgow legend and an Old Irish document. There are certainly two other medieval lives: the earlier partial life in the Cottonian manuscript now in the British Library, and the later Life, based on Jocelyn, by John of Tynemouth.

Mungo was brought up by Saint Serf who was ministering to the Picts in that area. At the age of twenty-five, Mungo began his missionary labours on the Clyde, on the site of modern Glasgow. He built his church across the water from an extinct volcano, next to the Molendinar Burn, where the present medieval cathedral now stands. For some thirteen years, he laboured in the district, living a most austere life in a small cell and making many converts by his holy example and his preaching.

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