what do the various marks chosen by craftsmen signify historically and how did the selection process work

Historically, a Mason's mark served as an individual signature cut into completed stones so that bookkeepers could credit each workman for his specific output upon the "bench" or "bank" 1. These marks functioned as proofs of personal identity and craftsmanship rather than as esoteric symbols, carrying no hidden doctrinal system 1. Outside of masonry, similar marks were mandated by statute across various medieval trades—including blacksmiths, coopers, pewterers, and goldsmiths—to enforce accountability and identify individual work 3.

Within the operative trade, the selection process allowed a workman who had completed his seven-year apprenticeship and passed examination as a Fellowcraft or Master to choose a mark by which his work could be identified before traveling as a free man 2. Regulations required that every Mason adopt a distinct mark that could not be confused with another workman's, keeping the design simple enough to chisel easily and record in administrative logs 1.

A theoretical distinction noted in operative accounts divides marks by their structural geometry. One tradition classifies marks into "blind" or false marks assigned to apprentices, which feature an equal number of points, and true marks given to passed Masons, composed of an unequal number of points (such as 3, 5, 7, 9, or 11 points connected by lines) 13. While later speculative rules generally require marks formed of odd points connected by straight lines, actual historical surveys of operative masonry across Europe show that craftsmen occasionally used curved designs, such as hearts or vessels, though straight-line geometric figures predominated 1.

Historically, Scottish masons generally maintained that there was no distinction of ranks in the assignment of marks—master masons were not given a special class of marks to distinguish them from their workmen 3. While a long-standing view held that false or "blind" marks with an equal number of points belonged to apprentices and true marks with an unequal number of points to fellow-crafts 3, records such as those of Aberdeen Lodge show that apprentices used similar marks to craftsmen, and continued using the same mark upon being promoted 3.

In selecting a mark, Scottish masons noted that the only strict structural rule was that it had to contain at least one angle 3. Circles were avoided unless combined with a line forming an angle 3. While speculative rules later developed requiring marks to consist of odd points connected by lines, the Grand Lodge of Scotland disclaimed responsibility for any ritual on the subject and laid down no official rules 1. Genuine curved marks were extremely rare among Scottish operatives—such as a single mark representing a vessel out of 265 found at Fortress Cathedral—though emblems like a heart or straight and curved combinations occasionally appear 1.

Regarding the selection process itself, sixteenth-century masons were not guided by any symbolic quality or geometric propositions when choosing a mark 3. If two masons from different areas met at the same work and shared a mark, one was required to temporarily alter his, or "difference" it, to avoid confusion 3. Marks were generally not inherited; examination of the Mary Chapel records revealed only a single instance of a Scottish craftsman adopting his deceased father's mark 3.

Marks were frequently formed as monograms using the initials of a member's name, or as geometric shapes like the equilateral triangle 3. Non-operative or speculative members also registered marks alongside operatives, sometimes selecting devices reflecting their own trades, such as a merchant choosing a pair of scissors 3.