The Protestant reformers were as much committed to higher education as their predecessors of the "old faith". They invited Andrew Melville (1545-1622), who had recently returned from Geneva, to become Principal of the University. In 1577 he secured a Royal Charter of Nova Erectio, which effectively re-established the University. Teaching improved and although finances remained precarious an ambitious new building was constructed in the High Street during the troubled years from the late 1620s until 1662. A well-stocked library was also created.
The majority of students intended to become ministers in the Reformed Church but an increasing number were the sons of gentry with other ambitions. Students still lived in the College and were required to wear red gowns and speak only in Latin. By 1702 there were some 400 students, most of whom now lived in lodgings. With the development of Glasgow's trade over the next fifty years more and more students came from commercial backgrounds and only stayed for a year or two. There were also significant numbers of Irish Presbyterians and English non-conformists, with a few from overseas, particularly North America.
The old system of regents teaching a number of subjects was replaced with professorial chairs in specific subjects. In 1712 the University reaffirmed its commitment to teach both law and medicine. There were distinguished professors by the mid-18th century, notably Francis Hutcheson (1730-1746), Adam Smith (1723-1790), Joseph Black (1728-1799) and William Cullen (1710-1790). The majority of students continued to study Arts, but only a very few ever graduated. Teaching was now in Scots or English.