On 15 May 1266 Henry "Almain" Cornwall (age 30) and John Warenne 6th Earl Surrey (age 35) fought for the King at Chesterfield [Map] during the Battle of Chesterfield. Henry Hastings (age 31), John Clinton, Roger Mandeville, John Eyvil, Baldwin Wake (age 28) all fought on the rebel side. The rebel Robert Ferrers 6th Earl of Derby (age 27) was captured.

New Chronicle by Villani Chapter 39. 13 Mar 1271. And now we return to our chief subject — how was slain Count Henry, earl of Cornwall (age 35), brother [cousin] of King Edward, in revenge for this, as we said before. The court was greatly disturbed, giving much blame therefor to King Charles, who ought not to have suffered this if he knew thereof, and if he did not know it he ought not to have let it go unavenged. But the said Count Guy (age 27), being provided with a company of men-at-arms on horse and on foot, was not content only with having done the said murder; forasmuch as a cavalier asked him what he had done, and he replied, “J’ai fait ma vangeance,” [I took my revenge] and that cavalier said, “Comment? Votre père fut trainé;” [How? Your father was dragged] and immediately he returned to the church, and took Henry by the hair, and dead as he was, he dragged him vilely without the church; and when he had done the said sacrilege and homicide, he departed from Viterbo, and came safe and sound into Maremma to the lands of Count Rosso, his father-in-law. By reason of the death of the said Henry, Edward, his brother, very wrathful and indignant against King Charles, departed from Viterbo, and came with his followers through Tuscany, and abode in Florence, and knighted many citizens, giving them horses and all knightly accoutrements very nobly, and then he came into England, and set the heart of his said brother in a golden cup upon a pillar at the head of London Bridge over the river Thames, to keep the English in mind of the outrage sustained. For the which thing, Edward, after he became king, was never friendly towards King Charles, nor to his folk. After like manner, Philip, king of France, departed with his folk, and came and dwelt many days in Florence; and when he was come into France, he buried the body of the good King Louis, his father with great honour, and had himself crowned with great solemnity at Rheims.

Divine Comedy Canto 12. Then I turned me to the Poet, and he said, "Let him now be first, and I second." A little further on the Centaur stopped above some folk who far as the throat were seen to issue from that boiling stream. He showed to us at one side a solitary shade, and said, "He cleft, in the bosom of God, the heart that still is honored on the Thames."¹ Then I saw folk, who out of the stream held their head, and even all their chest; and of these I recognized many. Thus ever more and more shallow became that blood, until it cooked only the feet: and here was our passage of the foss.

Note 1. In 1271, Prince Henry, son of Richard of Cornwall, was stabbed during the mass, in a church at Viterbo, by Guy of Montfort, to avenge the death of his father, Simon, Earl of Leicester, in 1261. The heart of the young Prince was placed in a golden cup, as Villani (vii. 39) reports, on a column, at the head of a bridge in London.