Gruffudd Fychan (died before 1370)
Gruffudd Fychan (c.1330–1369) was Lord of Glyndyfrdwy and Lord of Cynllaith Owain. As such, he had a claim to be hereditary Prince of Powys Fadog, and was a member of the Royal House of Mathrafal. His son, Owain Glyndwr, started the Welsh Revolt and became Prince of Wales.