There a new element was introduced into the struggle, for the right of the Roundhead force was commanded by Cromwell, who had raised and disciplined a body of cavalry called the Ironsides.

These men were all fanatics in religion and fought with a sternness and vigor which carried all before them.

In the eastern counties they had already done great service; but this was the first pitched battle at which they had been present.

Their onslaught proved irresistible.

The Royalist cavalry upon the left were completely broken, and the Roundhead horse then charged down upon the rear of the king's infantry.