The man who was Prince of Wales in 1399 came from what dynastic English house?
Dunstable Swan Jewel:  It was excavated in 1965 on the site of Dunstable Friary, and is presumed to have been intended as a livery badge given by an important figure to his supporters; the most likely candidate is probably the future Henry V of England, who was Prince of Wales from 1399. Henry V of England:  He was the second English monarch who came from the House of Lancaster.
House of Lancaster