William Sinclair, 4th Earl of Caithness

Succeeded c.1610, died 1650 Was granted the charters of 1630 from the Masons of Scotland, recognising that the position of Grand Master Mason of Scotland had been hereditary in the St Clair family since it was granted by James II in 1441. The original charters had been destroyed in a fire. William continued his father’s work to the Castle, building over the vaults up to the level of the courtyard. He died in 1650.