'The dusky mountains of the western Highlands often sent forth wilder tribes to frequent the marts of St. Mungo's favourite city. Hordes of wild shaggy, dwarfish cattle and ponies, conducted by Highlanders, as wild, as shaggy, and sometimes as dwarfish, as the animals they had in charge, often traversed the streets of Glasgow. Strangers gazed with surprise on the antique and fantastic dress, and listened to the unknown and dissonant sounds of their language, while the mountaineers, armed, even while engaged in this peaceful occupation, with musket and pistol, sword, dagger, and target, stared with astonishment on the articles of luxury of which they knew not the use, and with an avidity which seemed somewhat alarming on the articles which they knew and valued. It is always with unwillingness that the Highlander quits his deserts, and at this early period it was like tearing a pine from its rock, to plant him elsewhere. Yet even then the mountain glens were over-peopled, although thinned occasionally by famine or by the sword, and many of their inhabitants strayed down to Glasgow--there formed settlements--there sought and found employment, although different, indeed, from that of their native hills. This supply of a hardy and useful population was of consequence to the prosperity of the place, furnished the means of carrying on the few manufactures which the town already boasted, and laid the foundation of its future prosperity....'
Saint Mungo's life began mysteriously. According to the Catholic Encyclopedia (newadvent.org), his mother was named Thenaw, and was a daughter of British prince Lothus. His father is unknown. Kertigern, as the Saint is also known, began an austere mission life at age 25 in Cathures, on the Clyde, which became Glasgow.
Saint Mungo and Saint Mungo's Church appear in Walter Scott's "Rob Roy", from which the text above comes. Saint Mungo died on January 13, 603, and January 13 is his Feast Day.