William de Braose, Lord of Abergavenny (c. 1197 – May 2, 1230) was the son of Reginald de Braose by his first wife, Gracia de Briwere. The Welsh, who detested him, called him Gwilym Ddu (Black William). He succeeded his father in his various lordships in 1227, including Abergavenny and Builth.

He was married to Eva Marshall, daughter of the famous William Marshall. They had four daughters and coheiresses:

1. Isabella, wife of Prince Dafydd ap Llywelyn
2. Maud, wife of Roger Mortimer, 1st Baron Wigmore
3. Eleanor, wife of Humphrey de Bohun
4. Eve, wife of William de Cantelou

He was captured and imprisoned (as an act of retaliation) by Llywelyn the Great, ruler of most of Wales, in 1229, but was given relative freedom because he was related to the prince by marriage in several ways; his daughter, Isabella, was married to Llywelyn's only legitimate son. However, William then began an affair with Llywelyn's wife, the Princess Joan. The Chronicle of Ystrad Fflur entry for 1230 reads:

"In this year William de Breos the Younger, lord of Brycheiniog, was hanged by the Lord Llywelyn in Gwynedd, after he had been caught in Llywelyn's chamber with the king of England's daughter, Llywelyn's wife."

Llywelyn had William hanged on May 2, 1230. Joan herself was later pardoned.

External links

• http://freespace.virgin.net/doug.thompson/BraoseWeb/William5.htm