By 1648 the relations between the two had become so strained that there was some doubt about the support of Lancashire being forthcoming against the Scotch Invasion. Eventually the differences were overcome because the invaders were Scots, and the Lancashire troops rendered valuable service at the battle of Preston. But there was no common ground for the Presbyterians and Cromwell; and in 1651, when Charles II. marched through Lancashire, the county was really in his favour. The Earl of Derby, Charles' general in Lancashire, had an interview with the leading Presbyterians, and it was only the impossibility of reconciling their opinions, and the exhaustion of the county after nine years of war which prevented Lancashire from being completely raised in Charles' favour. The side of the war from which it appears as a class struggle is also illustrated in Lancashire. The head of the local royalists was James Stanley, seventh Earl of Derby, representing the great house of Stanley which had been for generations all-powerful in the north-west of England; the leaders on the other side were the lesser gentry who stood to gain by the weakening of his power, and behind them was the awakening spirit of the towns. The first event of the war in September, 1642, was Derby's unsuccessful siege of Manchester; the hardest fought engagement was the royalist capture of Bolton in 1644; the last scene, seven years later, was Derby's own execution in Bolton market place. These things are significant of the place which the towns were beginning to take. And with the Earl of Derby in 1651 died the last of feudalism in Lancashire. The geographical conditions had another effect in that as the two parties were divided the Parliament held in this respect the advantage. Their territory was the south and south-east of the county which was the most accessible part of it. Thus the royalists were cut off from the neighbouring counties, and once at least, in August, 1644, when Newcastle had overrun all Yorkshire and sent from Halifax a summons to Manchester, the moorland barrier saved the Lancashire Parliamentarians from having an invasion to face. Blackstone Edge was fortified and the difficulty of the ground was enough to secure the safety of the county.