Who was the last heir to the throne to die in battle?

The question of the title was asked of me by a friend recently.

Richard III was certainly the last English monarch to be killed on the battlefield, in 1485.

The question of the last heir to the throne is much more complicated. The only Prince of Wales to be killed on the battlefield was Edward of Westminster, the son of Henry VI, who was killed in 1471.

There is, however, a little doubt about this: the inexperienced prince and his mother led the remnant of their forces at the Battle of Tewkesbury with little real hope of success. Killed in battle, according to later Tudor legend Edward was taken prisoner by Richard, Duke of Gloucester and brought before Edward IV. When the young Edward insulted the Yorkist king, Edward IV ordered his immediate murder. He is buried at Tewkesbury Abbey. The problem is that he wasn’t legally heir to the throne at the time, though his moral claim seems secure:

September 1460 Duke of York returns to Wales, claims the throne and is named Henry VI's heir.

December 30, 1460 Queen Margaret's Lancastrian army defeats the Yorkists at the battle of Wakefield. Duke of York and Earl of Rutland killed.

Ironically, this has the key to the answer to: Richard Plantagenet, 3rd Duke of York, and father of Richard III, forced Parliament to recognize him, rather than the Prince of Wales, as heir to the throne. And he was then killed on the battlefield in 1460. (Incidentally, the son that was killed with him was not next in line after him, so we don’t need to fret about which was killed first.)

On 10 October, York arrived in London and took residence in the royal palace. Entering Parliament with his sword borne upright before him, he claimed the throne of England. Once again, his narrow support among his peers led to failure. After weeks of negotiation, the best that could be achieved was that York and his heirs would be recognised as Henry's successor. However, Parliament did grant York extraordinary executive powers to protect the realm, and with the king effectively in custody, York and Warwick were the de facto rulers of the country. On December 30, York and his forces left Sandal, possibly to obtain supplies. Intercepted near Wakefield by a larger Lancastrian force, York and his son were killed.

I don’t know who the last person that was both legally and morally heir to die in battle was. Any suggestions?

It’s interesting that the last heir to the throne to die in battle was father to the last monarch to die in battle.

Daniel Hill