12 The Square is known as the Principal’s Lodgings.
When the townhouse was first built in 1870–1871 by George Gilbert Scott it mainly housed the University’s Professors of Divinity but in 1962 No.12 and No.13 were reconfigured by W.N.W. Ramsay. It was decided by the University Court that the Principal’s Lodging, originally located in 13 The Square, would be centred on the west part of the building (No.12) and not the east as before. When the changes to the townhouses took place the new Lodging occupied the whole ground floor of both No.12 and No.13. The entrance to 12 The Square was also changed so that the house could be accessed from the north side. The existing entrance to No.13, opposite the Lion and Unicorn staircase, would be retained for the use of the Principal’s neighbour, who was assured of very generous accommodation on the east side (No.13) from the first floor upwards. The Principal's Lodging is the only building still in part-residential use and is also used for hospitality and corporate events.
12 The Square was first occupied by John Caird – first as Professor of Divinity from 1870 to 1873 and then as Principal of the University from 1873 to 1898.
Between 1898 and 1961, 12 The Square was occupied by the University’s Professors of Divinity. William Hastie, Professor of Divinity from 1895 to 1903, moved to No.12 from 13 The Square in 1898 and resided there until 1903. The next resident was W.H.M. Beckwith Reid who
was Professor of Divinity from 1903 to 1927 and lived at No.12 during this time. From 1927 to 1947, Professor of Divinity William Fulton
resided at No.12. John Gervase Riddell, was Professor of Systematic Theology at the University from 1935 until his appointment to the Chair of Divinity in 1947 and stayed at No.12 from 1947 until 1955. No.12’s last resident before the renovations was Ronald Gregor Smith, Professor of Divinity from 1956 to 1969, who lived at the townhouse from 1950 to 1960.
After its renovations in 1962, 12 The Square became the Principal’s Lodging. Sir Charles Haynes Wilson, was Principal and Vice Chancellor of the University from 1961 to 1976 during which time he lived at No.12. The next resident at No.12 was Sir Alwyn Williams, who was Principal and Vice Chancellor from 1976 to 1988. Sir William Kerr Fraser was Principal from 1988 until 1995 and lived at 12 The Square during this time. The Principal’s Lodging was next occupied by Sir Graeme John Davies from 1995 to 2003, followed by Sir Muir Russell from 2003 to 2009, and is currently engaged by Anton Muscatelli.