The University of Glasgow (abbreviated as Glas. in post-nominals; Scottish Gaelic: Oilthigh Ghlaschu) is a public research university in Glasgow, Scotland. Founded by papal bull in 1451 [O.S. 1450], it is the fourth-oldest university in the English-speaking world and one of Scotland's four ancient universities. Along with the universities of St Andrews, Aberdeen, and Edinburgh, the university was part of the Scottish Enlightenment during the 18th century. Glasgow is the largest university in Scotland by total enrolment and with over 19,500 postgraduates the second-largest in the United Kingdom by postgraduate enrolment.