Hirwaun Common  
The common itself existed before the invasion of the Normans and it was called “Hyrwenunworgan” is documented under a charter 1203 due to the fact of the grazing rights between the Cistercian Monasteries of Llantarnum (Carleon) and Margam.
The effect of the Norman Conquest was the marcher lords of Glamorgan would have assumed the rights of the of the last Independent ruler of Glamorgan Iestyn ap Gwrgant his father Gwrgant ap Ithel was rumoured to have granted the rights of the common of all men.
Hirwaun Common was a waste land of Miskin Manor and Glynrhondda over the common of grazing rulers over by the marcher lords of Glamorgan.
In 1547 Edward VI granted the lordships to Glynrhonnda and Miskin to William Herbert whom in 1551 became Earl of Pembroke.