Born: c. 1191
Died: 2 February 1237. Joan was buried at Llanvaes where her stone coffin was discovered in the early 19th century. This coffin can now be seen in Beaumaris parish church, Anglesey. The etching (right) appears in The Archaeological Album of 1845.

Father: King John of England
Mother: possibly Agatha Ferrers

Joan was married in 1205 to Llywelyn ap Iorwerth, Prince of North Wales.

Some writers blame the hanging of William de Braose by Llywelyn in 1230 on the discovery of some intrigue between William and Joan.

Child 1: Dafydd, Prince of Gwynedd

Child 2: Helen
= (1) John, Earl of Chester (d 1237 s.p.)
= (2) Robert de Quincy (d 1257)

Child 3: Gwladus Ddu

The attribution of some of Llywelyn's children to their mothers is uncertain but Dafydd, Gwladus and Helen are thought to be Joan's children.