The chapel was founded by William Sinclair, 1st Earl of Caithness of the Sinclair family, a noble family descended from Norman knights. It was constructed using the standard designs the medieval architects made available to the Earl. Rosslyn Chapel is the third Sinclair place of worship at Roslin - the first being in Roslin Castle and the second (whose crumbling buttresses can still be seen today) in what is now Roslin Cemetery.