This 6th century inscription was first recorded by one of Edward Lhuyd's assistants at "Pentre Yskythrog" in the middle of the highway. By 1777 it was by the roadside like a milestone. In the mid 19th century it lay in a hedge just over 4 miles south of Brecon; this is probably where it was photographed in c.1889. It is now housed in Brecknock Museum and Art Gallery.

Nash-Williams ECMW (1950) no. 68 / Redknap and Lewis (2007) B35