When is the earliest reference to the master mason degree?

The earliest reference to the Master Mason degree is found in the records of the Premier Grand Lodge of England, established in 1717. However, the degree itself likely existed in some form prior to this, as evidenced by mentions in earlier Masonic documents and manuscripts, such as the "Regius Poem" (circa 1390) and the "Cooke Manuscript" (circa 1500). The formalization and public recognition of the degree as part of the Masonic system occurred during the early 18th century.