It is thought that Merchiston Castle - a strong 15th century L-plan tower in Colinton, Edinburgh - was built around 1454 by Alexander Napier, the second Laird of Merchiston. It has six foot thick walls which rise five floors to the parapet and was the home of the Napiers, of whom John Napier (1550–1617) invented logarithms - well known to those of a certain age with an interest in mathematics!
Merchiston Castle was attacked by the garrison of Edinburgh Castle during the Civil Wars of the 1570s but the main damage occurred when it was converted into a school in the 19th century. At that time it became the centre of a cluster of buildings before clearance and restoration in 1958. The opportunity was then taken to install a painted ceiling of 1581 from Prestongrange.