It seems that in English 'older times' it was expected for the King or monarch to lead the armies in battle.
My research suggests that this was the case in the 12th century in the civil war between King Stephen and Empress Maud/Matilda (her champion being Robert of Gloucester an half brother). Note that since she was never recognized as monarch, she is mentioned only as a combatant1.
Both King Stephen and his son were on the battlefield, his son dying there (though note that his son was also never the monarch - due to his premature demise).
- Who was the last English/British monarch to be a combatant?
- Who was the last English/British monarch to die on the battlefield?
By 'combatant' I mean:
A person operating close enough to the battlefield that they might be taken captive in the event of 'loss of battle'.
A monarch does not necessarily need to actually 'draw a sword' to be in that position, but merely close enough to the battlefield that if it goes wrong, they are in imminent danger of capture (or execution/death by battle wounds).