Henry was born in August of 1386 (or 1387) at Monmouth Castle on the Welsh border. His father, Henry of Bolingbroke, deposed his cousin Richard II in 1399. With Henry IV’s ascension, the younger Henry became Prince of Wales and spent eight years leading armies against the rebellious Welsh ruler Owain Glyndwr. In 1403 Henry fought alongside his father against their former ally Henry “Hotspur” Percy in the Battle of Shrewsbury. During the battle, the younger Henry was hit in the face with an arrow but was saved by the daring surgical removal of the arrowhead.

Stories of the rakish young “Prince Hal” (expanded upon in Shakespeare’s “Henry IV”) are difficult to prove, though there may have been father-son tensions during the last years of Henry IV’s reign.

Henry IV died in 1413, and the 26-year-old prince took the throne as Henry V. Conspiracies soon arose among his onetime friends to unseat him in favor of Richard II’s heir Edmund Mortimer. In 1415 Henry executed Lord Scrope and the earl of Cambridge, the leading plotters, and defeated a rebellion led by his old associate John Oldcastle (the model for Shakespeare’s Falstaff).

Meanwhile, Henry was making demands of France—first for the return of Aquitaine to England in fulfillment of a 1360 treaty, then for a 2-million-crown payment, then for the king’s daughter Catherine’s hand in marriage. In 1415 Henry gathered his army and sailed for France.

Henry abandoned plans to attack Paris after the victorious but costly siege of Harfleur, in which one-third of his army died of dysentery. On October 25, 1415—the feast day of St. Crispin—Henry’s army defeated a much larger French force at Agincourt. Henry’s army of about 6,000 battled up to 30,000 French soldiers, who were forced by the terrain to advance in narrow formations that made them easy targets for Henry’s archers. The French advance was impeded by mud and their own mounting dead. All the while, Henry kept control of the battle, encouraging his troops and fighting hand-to-hand.

After the English took so many prisoners that Henry worried they might overpower their guards, he violated the rule of war by ordering their immediate execution. All told, the French lost as many as 7,000, while the English dead numbered at most a few hundred. Though not militarily decisive, the victory at Agincourt won Henry important allies and gained him a hero’s welcome on his return to England.

In 1417 Henry attacked France again, capturing Caen and Normandy and taking Rouen after a six-month siege in which he refused to aid 12,000 expelled residents left to starve between the city walls and the English lines. In 1420 the French king Charles VI sued for peace. The Treaty of Troyes placed Henry in control of France for the remainder of Charles VI’s life and promised that the English line would succeed to the French throne. Henry married Charles’ daughter Catherine. The royal couple arrived in England in 1421, and their only son, the future Henry VI, was born soon after.

Henry returned to France to deal with territories allied with the disinherited dauphin, the future Charles VII. In May of 1422 Henry won his last victory in the Siege of Meaux. He died on August 31, 1422, of battlefield dysentery.

Henry VI was less than a year old when he took the English and French thrones. By the time he was deposed in 1461, he had lost most of the French territories his father had won and England was riven by the War of the Roses.

In 1599 Shakespeare wrote his “Henry V,” including the St. Crispin’s Day “band of brothers” speech by which the eponymous king is most frequently remembered.