Named Ynysygrug, it was a lesser motte and bailey earthwork defence consisting of a wooden tower surrounded by a small fortified courtyard.

The fortification was for many years wrongly thought to be the burial place of Rhys ap Tewdwr or a druidic worship site.

"E. D. Lewis in his work The Rhondda Valleys provides us with an outline history of the mill that once stood in Tonypandy, and from which the town took its name".

With the extension of the Taff Vale Railway to Treherbert and Maerdy in 1856, the Rhondda grew as absentee landlords switched their interests from farming to mining.

Tonypandy, unlike the surrounding villages, then grew as a financial and social hub, providing services and amenities for the neighbouring communities.

[6] Although surviving only one season, the club transformed into Mid-Rhondda AFC, one of the most notable association football teams the Rhondda has produced.

[7] It was also used as the opening venue for the 1908–09 Kangaroo tour of Great Britain, when the visiting Australian rugby league team began its campaign with a match against Mid-Rhondda.