The maypole, comparable in height to that of the adjacent tower of St Andrew Undershaft, was used each Spring in a celebratory May Day festival. But at the festival on 1 May 1517 the City apprentices, angry against foreigners (presumably coming over here and taking their jobs) rioted and the authorities decided that 'Evil May Day' would be the last year of the festival. The shaft was kept, hanging on houses in Shaft Alley, but in 1549 some fiery preaching against the "idol" caused the Shaft Alley people to cut it into sections and each took the length that had hung on his house, as fire wood.
2016: Spitalfield's Life published a list of London riots in association with 'Adam Dent's London Riot Map', but the Maypole Riot is not included. But, 2017, IanVisits provides details.
