The first Grand Lodge was formed on 24 June the feast day of John the Baptist in 1717. This may arise from a very old tradition, since the Baptist appears to have been regarded as the patron of stonemasons in continental Europe during the Middle Ages. The guild of masons and carpenters attached to Cologne Cathedral was known as the Fraternity of St. John the Baptist. The earliest surviving record of Grand Lodge of Ireland installing a Grand Master is dated to 24 June 1725. As records of individual lodges appear in Ireland and in the Antients in England, it seems many of them met to install a new master twice a year, on the feast days of both the Baptist and the Evangelist.

https://en.wikipedia.org/wiki/St._John%27s_Day,_Masonic_feast