It was a political marriage, urged on by Thomas Cromwell, 1st Earl of Essex, concerning England's vital alliance with the Germans in the wake of the Truce of Nice.

Cromwell was not present, the Parliamentarians were commanded by the Earl of Essex. The action was fought on the 23rd, October 1642, the outcome was inconclusive

Thomas Kitson Cromwell has written:

'History & description of the ancient town and borough of Colchester, in Essex'

'Walks through Islington'

For parliament it was oliver cromwell, Sir Thomas Fairfax and the Earl of Essex. I was told that Prince Rupert lead most of the royal army but so did the king (charles i) himself along with Sir Ralph Horton and The Earl of Newcastle. Hope this helps!