I was going to follow up on the issue of Templar's and Sinclairs.
The Templar's were outlawed across Europe in 1309-1312 their lands and property going to the local Kings, the Pope or the Knights Hospitallers of St. John. Hence it is very unlikely that the Rosslyn Chapel ties directly to any Templar Order or History directly as the construction was in the mid 1400's. I am unaware of any St. Clair/Sinclair being a member of the Templar Order. As this was a somewhat secret organization it is hard to say but this part of History is mostly unstudied. If they were it may tie to the Sinclairs of Normandy which did not all migrate to Scotland after 1066.
However the Rosslyn Chapel is an enigma because it does tie to many of the symbols of the Masonic Order but was built well prior to the Freemasonry organization which came into being after 1600 in England & Scotland. Hence it was after the Templar power and before the Freemason movement.
Hence it may be a link to a former time and culture, because the construction itself would not be unfamiliar to present day masonry which places significant importance to the symbolism of the original Temple of Solomon in Jerusalem. Now in the chance I am losing the continuity for some of our friends, the Templar Order and the Masonic Order both have deep cultural underpinnings in theology and connections to the Holy Land and Judaic Roots.
Members should be very interested that the Sinclairs were the head of the Masons in Scotland for a long period. Given that the Masons in the 1700's were the power brokers and possessed valued construction knowledge, this is something of a heritage to be proud of. In the United States, citizens should recall that most of the founding fathers were Masons, and Washington D.C. reflects much masonic thinking. The first masonic lodge in Nova Scotia was started by a Sinclair, and Sinclairs and Masons seem intertwined in history.
John, you might want to explore further with the Curator of the Rosslyn Chapel as to the links between Templar's and Masons, and the study behind the cement carvings. I personally am rather persuaded that there is, however I want to learn more. If one of our archaeological friends are looking for a doctoral study, the analysis of the carvings at Rosslyn is a great topic. Aside from being one of the fine works of art in architecture, it is also the container of great mythic and symbolic values and has much unstudied history in its carvings and architecture.
The Temple and the Lodge by Michael Baigent and Richard Leigh,
Corgi Books, 1989.
(paperback and a great historical read, contains pictures of Rosslyn Chapel.)
The origins of Freemasonry, Scotland's Century 1590 to 1710. David Stevenson, Cambridge University Press 1988. (paperback, a scholarly read)
Enjoy and I hope this adds to your understanding and appreciation of the Greater Sinclair family history.