He was the munificent founder of Marischal College, Aberdeen on whom the highest honour available to a subject was conferred in 1609 when he was commissioned to represent the King in the Scottish Parliament. He died in 1623 and was interred in this place of sepulchre where not only he but many successive generations of Keith were gathered to rest.

Some authorities aver that this mausoleum was at one time a private chapel with a burial vault below. In the session records there is a mention of a “Marischal Aisle” and it is concluded that latterly a top storey of the Aisle was added, opening into the Church, as a private balcony for the use of the Keiths when they attended services. The “loft” would appear to have been demolished when the “new” church was built in 1782 and the remainder of the building left uncared for for over a century, the vault was open and trees grew inside, but it was restored and re-roofed in 1914 by Marischal College, Aberdeen, in memory of their founder and the underground vault closed up.

“At one time the Aisle was nevertheless connected to the original church which stood until 1782 on part of the site of the present church, but the old doorway at the North end has been blocked up as is a former window at the opposite extremity and is still recognisable today. The side door to the present church is surmounted by a niche, and on the lintel is cut the date 1582 and the initials G.K. “with the Keith arms”.

Inside this handsome aisle are semi-circular arched recesses in the walls and some interesting relics are preserved including sculptured stones and four curious old stands for holding collection basins at the Church door. There are also a few old fonts, including one found at East Carmont which belongs to the 15th or 16th century and a circular one belonging to the 13th or 14th century found on the western boundary of the parish, not far from Temple of Fiddes.

There is also a stone tablet, with delicately carved royal Arms fast crumbling away.

Also in the Aisle in regular use is a massive table, dedicated by the Rev. J G. W Hendrie to the memory of Sir Walter Scott which was made of wood from an old elm that grew in front of the manse and under which Scott is said to have sat when he visited Dunnottar in 1788.

Outside beneath the west wall of this tomb, the graves of William Ogilvy of Lumgair and Catherine, his wife, recall the heroic defence of Dunnottar Castle by their son, George Ogilvy of Barras, whose gallantry and courage saved the Regalia of Scotland from falling into the hands of Cromwellian army.