"Sheath makers may have been responsible for the manufacture of leather armour used for both men and horses. Such armour is known both from documents, such as the inventory of Sir Simon Burley (executed in 1388) where a helmet of quier bouylle is mentioned, or from actual examples such as the shoulderpiece of leather with embossed designs of birs in foliage from London"

Blair, John, and Nigel Ramsay. English Medieval Industries: Craftsmen, Techniques, Products. London: Hambledon Press, 1991. Page 315

Piece of armour referred to is "A Fragment of leather armour for the right upper arm, 14th century (British Museum 56, 7-1, 1665)