The contemporary narratives are not more valuable than most mediæval chronicles in determining topography with precision, and the battle-field of Barnet has now been so much enclosed and built over that little can be discovered from examination of the ground. In the fifteenth century Gladsmuir Heath, as it was then called, was open ground, as the name implies: nor is there any trace in the narratives of the battle having extended over the rough broken ground which lies east of the great north road towards Monk's Hadley. The only topographical point made in the official Yorkist narrative is that Warwick, who was first on the field, arranged his men more than half-a-mile north of Barnet "under an hedge-side." There can nowhere have been a great length of hedge, sufficient to protect even a large part of Warwick's front; but he may well have taken up a line of which the southern boundary of Wrotham Park would form nearly the centre.[43] Nothing however turns on the exact shape of the ground: the battle was, like most others of the age, a straightforward engagement all along the line. Edward was anxious to make sure of fighting on the morrow: he had nothing to gain by delay, and might lose much, for Lancastrian forces were gathering in Kent. He therefore under cover of the darkness moved up so near to Warwick's line, that it would be impossible for either party to retire without engaging. So near did he venture that Warwick's guns, which were kept firing during the night, sent their shot harmlessly over the heads of the Yorkists. When day dawned on Easter Sunday, April 14, Gladsmuir Heath was enveloped in so thick a mist that neither party discovered at first that each army outflanked the other on the right.[44] The battle began in the usual way with an ineffective cannonade and some flights of arrows, and then they came to close quarters. As might be expected, Montagu and Oxford on the Lancastrian right defeated Edward's left, which fled through Barnet, pursued by Oxford, though Montagu seems not to have quitted the line of battle. In the centre the king in person engaged in an obstinate struggle with Somerset, and slowly gained some advantage. Warwick on the left was partially outflanked by Gloucester, but held his ground fairly well, though he was gradually forced back on the centre. In the thick fog nothing could be seen a few hundred yards off: thus Warwick remained ignorant of the success of Oxford, who, in his turn, was so completely bewildered by the fog that when he turned back, after driving his own immediate opponents through Barnet, he lost his way completely, and instead of taking Edward in rear as he presumably aimed at doing, went past the contending lines, and came upon the reserve of his own side. Here occurred the fatal mistake which ruined Warwick's chance of victory. In the mist the silver star of the De Veres was mistaken for Edward's cognizance, a sun with rays: Oxford's men were received with a volley of arrows.