 The rebellion broke out into the open on Saint John's Day, when the Tatars massacred Russian merchants and envoys present at the annual Kazan Fair.A huge army of the Kazan and Nogai Tatars then advanced towards Nizhny Novgorod and besieged the city.The affair was decided by 300 Lithuanian archers, who had been captured by Russians in the Battle of Vedrosha and lived in Nizhny in captivity.