Oliver Cromwell was the leader of the Parliamentarians in the English Civil war.
I think you may be referring to Edward Longshanks.
If so, yes, he did conquer Wales, with an army half of which was made up up Welshmen who didn't like the current ruler, Llywelyn ap Gruffydd.
Over 9000 of his 15,500 men were Welsh.
His campaigns against the Welsh almost broke him, and it was this which ultimately led to his failure to truly conquer our friends in the north. (Matter of debate, especially if Foxgun Tom reads this..! )
:clapper:
what have you welsh or scottish ever won