For Robert Mason: Welcome to the Sinclair net. I am not a Mason, but as a Commissioner for the Clan Sinclair for many years, I have had a definite interest in the Septs and Associated Families of our clan, though most of my questions remain unanswered. One of our five sept names is Mason, and I have always supposed that due to the great amount of building done by the Rosslyn earls in the 14th century, the craft of masonry would have been a major player in the Sinclair scheme of things. In the middle ages, large buildings were being built of stone because woodworking tools had not been developed. Stone Age man learned to shape and arrange stone in it's varied forms provided by nature and the environment, so it's not unusual that people who followed this craft and were called masons should have taken that as a family name quite early in the course of human history. It follows that the Sinclairs needed many people of that name to carry out their chapel and castle projects at Rosslyn, and that close association with and in support of the Sinclairs would give the Masons special consideration as a sept. They are entitled to wear the Sinclair tartan and be members of the Clan Sinclair Association, U. S. A.
I had also assumed that the Masons of the Middle Ages would have been centered around places where many of the craft families were established for exceptionally long projects, such as Rosslyn Chapel, and the building of the Sinclair Castle in the Orkneys. On the other hand, they must have also been involved in many similar long-term jobs, and the presence of a stonemason was not unusual anywhere in the world during the past several thousand years. Why would one family wind up with the name Mason?
I'm sorry I bring more questions than answers, but if you find something which explains the name in connection with Sinclair, I'm sure we would all like to hear about it.