midday
These opened with the decapitation of three bulls : a rite said to commemorate some long-forgotten dispute between the inveterate enemies , Venice and Aquileia . The bulls , preceded by halberdiers and trumpeters , and surrounded by armed attendants , were led in state before the ducal palace , and the executioner , practised in his bloody work , struck off each head with a single stroke of his huge sword . This slaughter was succeeded by pleasanter sights , such as the famous Vola , or flight of a boy from the bell-tower of Saint Mark 's to a window of the palace , where he presented a nosegay to his Serenity and was caught up again to his airy vaulting-ground . After this ingenious feat came another called the `` Force of Hercules , '' given by a band of youths who , building themselves into a kind of pyramid , shifted their postures with inexhaustible agility , while bursts of fireworks wove yellow arches through the midday light . Meanwhile the crowds in the streets fled this way and that as a throng of uproarious young fellows drove before them the bulls that were to be baited in the open squares ; and wherever a recessed doorway or the angle of a building afforded shelter from the rout , some posture-maker or ballad-singer had gathered a crowd about his carpet . Ash Wednesday brought about a dramatic transformation . Every travesty laid aside , every tent and stall swept away , the people again gathered in the Piazza to receive the ashes of penitence on their heads , the churches now became the chief centres of interest .