He was born to a Marcher family and was possibly of mixed Anglo-Welsh origin, holding lands that would lie in the present-day Radnorshire district of Powys and in Herefordshire.
[7][8] His role in the royal household ended in dismissal in 1388, but he remained politically active and was present at peace negotiations with France in 1389 that resulted in a three-year truce.
Studying Clanvowe's devotional treatise "The Two Ways", McFarlane has argued that heresy can be seen where the knight fails to discuss many parts of the English Church he would in that case have rejected, for example the efficacy of the sacrament.
Here he condemns his own knightly class, claiming they (and other Christians) should live a meek life and avoid indulging in the pleasures of this world, which can only lead to hell.
[29] Clanvowe's best-known work was The Book of Cupid, God of Love or The Cuckoo and the Nightingale, a debate poem influenced by Chaucer's Parliament of Fowls.
Staley too has claimed the poem can be seen as a criticism of elaborate courtly language under Richard II, with the nightingale complaining that the cuckoo is too hard to understand.
The Cuckoo and the Nightingale had previously been attributed to Chaucer, but the Encyclopedia of Medieval Literature notes the absence of direct evidence of that when linking Clanvowe with the work.