In common with other trades or mysteries, medieval masonry recognised three grades of craftsman;— the apprentice, the journeyman, and the master. An apprentice who had learned his craft became a journeyman, qualified to do all manner of masonic work. The master was also qualified as a project manager, often functioning as architect as well. He would sketch the day's work on a tracing board for execution by the journeymen and apprentices. The Schaw Statutes of 1598 show how this had evolved in the lodge system of Scottish masonry. An apprentice, after serving his term of seven years, could elect to pay to join a lodge, becoming an "entered apprentice". (Alternatively, he could elect to freelance on the lower grades of building work as a "Cowan".) The journeymen were referred to as "fellows" or "fellows of the craft", which accords with the Regius poem's injunction (line 51) that masons should "calle other felows by cuthe". The members of the lodge were "Brithers" (brothers), a Scottish legal term for those bound to each other by oath. The Master was simply the mason in charge of the lodge, or one who had held that distinction.