Merchiston Castle is a 15th century castle which is famous for being the birthplace in 1550 of John Napier, the discoverer of logarithms, and the 8th Laird of Merchiston.

The castle is thought to have been built around 1454 by Sir Alexander Napier, 2nd Laird of Merchiston. Sir Alexander’s son, Sir John Napier, 3rd Laird of Merchiston, married Elizabeth Menteith, a daughter of Murdoch Menteith of Rusky and a granddaughter of Margaret, sister of Isabella, Countess of Lennox. In 1460 the Countess of Lennox, eldest daughter of Donnchadh, Earl of Lennox, died. Her sons and husband had predeceased her, as had her two sisters, Elizabeth and Margaret, and so the Earldom of Lennox was divided between her sister’s heirs and Elizabeth Menteith inherited a quarter of the Earldom.

Elizabeth’s sister, Agnes Menteith, who married John Haldane of Gleneagles, also inherited a quarter of the Earldom, while Sir John Stewart of Darnley inherited the other half of the Earldom. In 1493 John Haldane and his son, James, reached an agreement with Sir John whereby they renounced their claims over the superiority and tenandry of their quarter of the Earldom.

In May 1490 Elizabeth Menteith and her son, Archibald Napier of Edinbellie, reached an agreement with John, Earl of Lennox, whereby they renounced their claims over the superiority and tenandry of their quarter of the Earldom.

The tower passed in and out of Napier hands over five centuries, and in 1833 William Napier, the 9th Lord Napier, let the castle to Charles Chalmers, who established Merchiston Castle School in the building.

The school moved to Colinton in 1930, and by 1935 the castle had passed to the Edinburgh Corporation. It remained unoccupied and deteriorating until 1956 when it was decided that the castle would be the centrepiece in the development of the new Napier Technical College (now Napier University).

Originally a five-storey L-plan tower and surrounded by a barmkin wall, it had a drawbridge at second floor level some 4.3m above the ground (discovered during the restoration work in 1958).

The castle is built on a rocky outcrop – hard to envisage with all the concrete surrounding it, but still visible at the base of the tower in places.

In the late 17th century the present roof and buildings above the parapet walk were added, possibly by the Lowis family.

A number of outbuildings were added while the castle was being used as a school, although these were removed during renovation work. One extension remains to the north, now pierced by a corridor connecting the castle to other campus buildings.

Within Merchiston Castle is an ornate painted ceiling dating to 1581, which was removed from Prestongrange House.