Oliver Cromwell did have Welsh blood. It seems that one Morgan Williams married a sister of Thomas Lord Cromwell. His son Sir Richard Williams seems to have taken the name Cromwell and was given large parts of the Neath Abbey lands on the Dissolution of the Abbey.

Robert Cromwell a grandson of Sir Richard married Elizabeth, a daughter of Sir Thomas Stuart of Ely and in 1599 they had a son - Oliver Cromwell, Lord Protector.

When Oliver Cromwell came to Glamorgan [Civil War]he tried to get the cooperation of some of his Williams cousins. He wrote to the Williams family of Aberpergwm reminding him of their relationship.

This placed the Williams family in a difficult position because they were also connected through marriage to some of the great estates of Glamorgan ( Williams was married to a sister of one of the Bassetts, who was Sheriff at that time) who were all Royalists.

In 1648 a group of Cromwells troups passed through the Vale of Neath and fired cannon shot at Aberpergwm and it seems that as Williams was mounting his horse a cannonball carried off his leg.