Encouraged by the triumph at Wakefield a jubilant Margaret left Scotland and joined the Lancastrian forces at York. Margaret brought with her a force of Scots. These men were one of the conditions of the betrothed of James III of Scotland’s daughter, Mary of Guelders, to the infant Edward Prince of Wales. Another was Berwick castle, which would revert to Scottish control. These machinations by a French queen were not well received in England. In York the Lancastrian nobles renewed their oaths of fealty and affirmed Edward’s right to the throne of his father thereby repudiating the Act of Accord. Opting to strike while the iron was hot the army left York on 20th January bound for London and bent on recovering Henry. On the march the army spread out across a wide front to forage as it moved south. Consisting for the most part of unpaid and undisciplined troops the foraging was accompanied by widespread plundering, arson, and rape. Dire stories of the troops misbehaviour preceded them as they approached London. The defeat at Wakefield and the advance of the rampaging Lancastrian army produced perturbation in London. Prompted by the civic leaders of the town and the southern shires the remaining Yorkist lords under Warwick began amassing a force and on 12th February Warwick left London for St Albans. He may have hoped to rendezvous with the Duke of York but this did not eventuate. In the west York’s victory at Mortimer’s Cross on 3rd February had not ensured peace in the region. Both the Earls of Pembroke and Wiltshire had escaped with substantial forces. The presence of this threat may explain York's absence from the coming battle. When Warwick reached St Albans he spread his army of 12,000 men across a front of three and a half miles from St Albans towards Welwyn. Over the next four days this line was heavily entrenched with field works, cannon, caltrops and fishing nets laced with metal spikes. Perhaps the most extensive works were on Bernard’s Heath a piece of high ground three quarters of a mile northeast of St Albans. Beech Bottom, an Iron Age ditch in places some 30 feet deep, bound the heath on three sides. The troops and the works faced north and northeast, the direction Margaret’s army was expected to appear from. The 15,000 strong Lancastrian host reached Royston northeast of St Albans on the 15th or 16th of February. At this time they probably became aware of the Yorkists deployment and their defensive preparations. To continue marching south on London would have exposed the Lancastrian column to a flank attack while on the march and to move directly against the enemy would have involved frontally assaulting significant fortifications. Possibly under the guidance of Andrew Trollope the veteran soldier, they instead adopted a radical strategy. The army performed a flank march from Royston to Dunstable on the 16th. After a short rest at Dunstable they undertook a night march to St Albans along Watling Street. This brought them to the outskirts of the town as the winter dawn was breaking.