The Gwernyfed estate is of ancient origin; it is reputed to have been given by Bernard de Neufmarché (c. 1050 – c. 1125), the earliest of the Norman marcher lords, to Peter Gunter.

David Williams (d.1613), made his fortune in the law, serving as attorney general for South Wales from 1581-1595, Recorder of Brecon 1581-1604, Serjeant-at-law in 1593 and a judge of the King's Bench in 1604.

His earnings funded extensive land purchases including the Gwernyfed estate which he bought from John Gunter in 1600.

It contains a screens passage on which Charles I is said to have left a coded message for Prince Rupert of the Rhine when the king stayed at the house after the Battle of Naseby in 1645.

[b] Charles was the guest of Sir Henry Williams (c.1603-c.1656), a staunch royalist on whom the king had bestowed a baronetcy the previous year.

The interior retains much of the original medieval hall plan, with a screens passage bisecting the house.