Glasgow grew from a small rural settlement on the River Clyde to become the largest seaport in Britain. Expanding from the medieval bishopric and royal burgh, and the later establishment of the University of Glasgow in the fifteenth century, it became a major centre of the Scottish Enlightenment in the eighteenth century. From the eighteenth century onwards, the city also grew as one of Great Britain's main hubs of transatlantic trade with North America and the West Indies.
In the late-19th and early-20th centuries, Glasgow's population grew rapidly, reaching a peak of 1,127,825 people in 1938. Comprehensive urban renewal projects in the 1960s, resulting in large-scale relocation of people to designated new towns; such as Cumbernauld, Livingston, East Kilbride and peripheral suburbs, followed by successive boundary changes, reduced the population of the City of Glasgow council area to an estimated 615,070, with 1,209,143 people living in the Greater Glasgow urban area. The wider metropolitan area is home to over 1,800,000 people, equating to around 33% of Scotland's population. The city has one of the highest densities of any locality in Scotland at 4,023/km2.
The origin of the name Glasgow is disputed. It is common to derive the toponym from the older Cumbricglas cau or a Middle Gaelic cognate, which would have meant green basin or green valley. The settlement probably had an earlier Cumbric name, Cathures; the modern name appears for the first time in the Gaelic period (1116), as Glasgu. It is also recorded that the King of Strathclyde, Rhydderch Hael, welcomed Saint Kentigern (also known as Saint Mungo), and procured his consecration as bishop about 540. For some thirteen years Kentigern laboured in the region, building his church at the Molendinar Burn where Glasgow Cathedral now stands, and making many converts. A large community developed around him and became known as Glasgu (often glossed as "the dear Green" or "dear green place").