If you haven't done so yet, read my Introduction to the Allied Masonic Degrees, to which this post is a follow-up.
This degree is staged in a subterranean vault. Its meetings are composed of 27 members. It features the number 9, and the drama involves an unwitting intruder's entrance into the vault. This degree teaches us not to make hasty judgments and emphasizes the importance of being properly Tyled (guarded).
All of the traits I just listed are also present in the first half of the Select Master Degree of Cryptic Masonry. Scottish Rite’s 6°, Intimate Secretary, is also very similar. It is possible that one of these degrees was a source of inspiration for the others, or perhaps they were originally the same degree and have drifted apart slowly owing to a long separation of time and distance.
The vault in this degree is called the "Mystic Chamber" and the degree itself was for a while conferred as a Side-Degree by the Scottish Rite, and was then known as the "Select Masons of the 27."
Unlike the Select Master Degree in Cryptic Rite, Grand Tilers of Solomon does not explicitly mention the Nine Arches (however, the number 9 does come up in other contexts), neither does it make any deliberate connections with the story of the Royal Arch Degree. It is my opinion that this degree was the source upon which was grafted the story of "the Deposit of the Word" in order to formulate the Select Master Degree and complete the circle of perfection in Ancient Craft Masonry.
Steps to the Endowment.
6 years ago