Violent confrontations between town and gown erupted on a recurring basis. One of the most famous was the Battle of St. Scholastica Day, which occurred on 10 February 1355, at the University of Oxford. An argument in a tavern – a familiar scenario – escalated into a protracted two-day battle in which local citizens armed with bows attacked the academic village, killing and maiming scores of scholars. The rioters were severely punished, and thenceforth, the Mayor and Bailiffs had to attend a Mass for the souls of the dead every St. Scholastica's Day thereafter and to swear an annual oath to observe the university's privileges. For 500 years, Oxford observed a day of mourning for that tragedy.