St. Machar became a Cathedral in the 1130s when the seat of the Bishop was transferred from Mortlach, near Dufftown to Old Aberdeen under David I. By 1165 a Norman style cathedral stood on the site. In the 13th century the Cathedral had to undergo extensive restoration. This was started under the instruction of Bishop Cheyne (1282 to 1328).
In 1305 Sir William Wallace was hung, drawn and quartered and his dismembered body was sent to different parts of Scotland. Whether his left arm was indeed, as rumour suggests, interred within the walls of St. Machar's is not known for sure.
St. Machar's Cathedral is one of only a handful of churches in Scotland containing a set of bells hung for change ringing. Its eight bells were cast between 1906 and 1911 by Mears & Stainbank for St. Stephen's, West Ealing, London. The church was declared unsafe in 1979, and the bells were removed for storage. They were acquired by the Cathedral and, after refurbishment by Eayre & Smith, were installed in the south tower in 1987.