Notes:
Holy Roman Emperor. Sources differ over which Isabel Frederick married, some say Isabella daughter of John I Lackland of England and some say daughter of John of Brienne King of Jerusalem and Emperor of Constantinople. King of Naples and Sicily 1197.
II married Empress of Germany Isabella Plantagenet on 20 Jul 1235 in Worms Cathedral, Germany. Isabella (daughter of King of England John I "Lackland" Plantagenet and Countess of Angoulême Isabella Taillefer) was born in 1214 in Gloucester, Gloucestershire, England; died on 1 Dec 1241 in Foggia, Naples, Italy; was buried in Andria, Sicilia, Italy. [Group Sheet] [Family Chart]