General Notes

Richard was born January 5 1209 to King John of England and his second
wife (not third) Isabelle d'Angoulême. Isabelle was the daughter (not
sister) and heiress of Adhemar, Comte d'Angoulême, by his wife Alice
de Courtenay (herself a cousin of French King Philippe II). King John
had kidnapped her from her fiance, Hugh de Lusignan, in 1200. In 1257
Richard was elected King of the Romans (emperor-elect of the Holy
Roman Empire), was crowned and made several trips to Germany, but
never had much influence there.

Richard married Isabel Marshal in 1231 in what seems to have been a
love match, but she died in 1240 leaving one surviving son, Henry. He
then remarried in 1243 to Sancia de Provence, the sister of Queen
Eleanor, his brother Henry's wife. This made him brother and
brother-in-law to King Henry II of England. Richard and Sancia had one
surviving son before she died in 1261. He remarried lastly to Beatrix
von Valkenburg, but they had no children. Richard's eldest son and
heir, Henry, was murdered by his Montfort cousins in 1271 while
praying in a cathedral in Viterbo, Italy. His second son, Edmund, from
his second marriage, succeeded him as Earl of Cornwall but died in
1300 sans issue.

Richard had several illegitimate children -- I have Joan de Cornwall,
daughter of his illegitimate son Richard de Cornwall, as the wife of
John Howard.