Today is the 490th anniversary of the (appropriately named) xenophobic Evil May Day riot (also Ill May Day) that took place in the City of London in 1517. If nothing else it is yet another reminder of what happens when people listen to demagogues (as if history isn’t full of examples...).
Two weeks before the riot an inflammatory speech was made at St Paul’s Cross (a preaching cross outside the cathedral). The speaker Dr Bell called on all "Englishmen to cherish and defend themselves, and to hurt and grieve aliens for the common weal".
Over the next two weeks there were sporadic attacks on foreigners but things came to a head late on 1 May. Although a 9pm curfew was announced for the night of 30 April/1 May a mob of apprentices (who in those times seemed to form the backbone of any riot!) formed which over the next few hours attacked foreigners, looted their houses and freed prisoners jailed for previous attacks on foreigners
The under-sheriff of London, Thomas More (later canonised of course but never cannonised as he was in the Simpsons!), unsuccessfully tried to disperse the mob. The riot subsided after a few hours. Nobody was killed during the riot but several hundred rioters were arrested of which 13 were tried for treason and executed on 4 May.