There was a violent and protracted dispute between Humphrey de Bohun, Earl of Hereford and Gilbert de Clare, Earl of Gloucester, after the latter erected Morlais Castle in 1287. One clash between the two Earls is known as the 'Battle of Maesvaynor'. The church at Vaynor was set on fire and de Clare's men were routed. The dispute was finally settled in 1292 by Edward I, with forfeiture of their estates and fines.
Sources: Archaeologia Cambrensis, vol.5, 1859, pp.102-110; J.E.Jenkins, Vaynor History and Guide, 1897, pp.74-8.
The site is marked on early Ordnance Survey 25 in and 6in maps as "Site of Battle (A.D.1286)" B.A.Malaws, RCAHMW, 16 May 2006.