An extraordinary effort in its time, at the end of the late Middle Ages and the beginning of the Renaissance, work on the chapel began in 1446 and was personally overseen by Sir William St. Clair, the third and last St. Clair Prince of Orkney. According to an account written in 1700 by Father Richard Augustine Hay, Canon of St. Genevieve in Paris. Sir William inspected each of the hundreds of images in draft form in wood before giving it to the masons to carve in stone. Fr. Hay refers to various builders and masons as coming from "other regions" and "foreign kingdoms", with France as a good bet.
Although Rosslyn Chapel took nearly 40 years to build, contrary to popular belief, Sir William was not a Knight Templar nor a Freemason. Rosslyn was begun in 1446 -- much later than the dissolution of the Templar order (1312) and much earlier than the official beginnings of Freemasonry (1717), with the establishment of the Grand Lodge of England.
There is no documented historical evidence for a medieval Knights Templar connection with Rosslyn Chapel itself; further, the Templars did not build Rosslyn Chapel. However, not far away, at the nearby village of Temple, still stand the ruins of what was once the genuine headquarters of the Scottish Knights Templar, then called Balandtradoch. So the real Templar connection is not, in fact, at the site of Rosslyn Chapel, it is at the village of Temple, where the ruins of the Scottish preceptory can still be seen today.
Although Rosslyn Chapel was generously endowed by its founder, Sir William St. Clair, and by his grandson, by the time of the tumultous 16th century, the Reformation had a devastating effect on religious sites in Scotland. Many Catholic churches, altars and furnishings were badly damaged or destroyed, and the Rosslyn Chapel, too, fell into disuse. In 1650, Oliver Cromwell's troops attacked nearby Rosslyn Castle; in addition, his troops also housed his horses in nearby Rosslyn Chapel as well. Some believe this may have helped to save the chapel from further destruction, claiming that Cromwell was a Freemason, and that this may have been why he did not order the chapel destroyed. Yet there is no direct evidence that Cromwell was a Freemason, according to the Grand Lodge of England.
In 1688, an angry Protestant mob from Edinburgh and Roslin village pillaged and burnt the castle and further damaged the chapel, which remained abandoned until 1736, when James St. Clair began repairs. Given this turbulent history, we are fortunate indeed to have Rosslyn Chapel in all its glory today.