Saint Mungo is the commonly used name for Saint Kentigern (also known as Kentigernus (Latin) or Cyndeyrn Garthwys (Welsh)). He was the late 6th century apostle of the Brythonic Kingdom of Strathclyde in modern Scotland, and patron saint and founder of the city of Glasgow.
In Wales and England, this saint is known by his birth and baptismal name Kentigern (Welsh Cyndeyrn). The derivation of the name is probably Brythonic *Cuno-tigernos from the stems *cun- 'hound' (Welsh ci 'dog') and *tigerno- 'lord, prince, king' (Welsh teyrn 'monarch') - both common elements in British names. The evidence is based on the Old Welsh record Conthigirn(i). Other etymologies have been suggested, including British *Kintu-tigernos 'chief prince' based on the English form Kentigern, but the Old Welsh form above and the Old English Cundiʒeorn don't appear to support this. The epithet 'Garthwys' is of unknown meaning. In Scotland and far northern part of England, he is often called by his pet name of Mungo, possibly derived from the Brythonic equivalent of Welsh fy nghu meaning 'my dear(one)'. An ancient church in Bromfield, Cumbria is named after him, as are Crosthwaite Parish Church and some other churches in the northern part of the modern county of Cumbria (historic Cumberland).