The received account is precise: on 24 June 1717, four London lodges met at the Goose and Gridiron alehouse in St Paul's Churchyard and constituted the first Grand Lodge. The date is engraved on the fraternity's own sense of itself, and its tercentenary was marked in 2017.
The difficulty is the source. The 1717 meeting is not recorded in any document written at the time. It appears first in James Anderson's New Book of Constitutions of 1738, twenty-one years afterwards, in a historical preface by an author whose earlier 1723 Constitutions, written closer to the events, does not mention it. The Grand Lodge's own minutes do not begin until 1723.
Andrew Prescott and Susan Mitchell Sommers set this problem out in detail in work published for the tercentenary itself, which is an unusual thing for a commemorative occasion to host. Their argument is not that the meeting is an invention, but that a single retrospective account by an interested author, unsupported by contemporary record and contradicted in emphasis by that author's own earlier book, cannot carry the weight placed on it. They suggest the organisation of a grand lodge was more plausibly a gradual process across the early 1720s, and that 1717 is a foundation narrative composed after the fact to give it a clean origin.
The wider history is not affected. Lodges of accepted, non-operative members are attested in Scotland from the late sixteenth century and in England through the seventeenth, and Margaret Jacob's work established how thoroughly lodge sociability was woven into eighteenth-century European political culture. The fraternity's antiquity is not in question.
What is in question is a specific date, and the reason it is worth raising is methodological rather than deflationary. An institution that keeps unusually good records of itself from 1723 onwards has, for the years before that, exactly one late and interested witness. The distinction between what an organisation documents and what it remembers is visible here more clearly than almost anywhere else in this collection.