The newly crowned Henry V of England seized the opportunity presented by the mental illness of Charles VI of France and the French civil war between Armagnacs and Burgundians to revive the conflict. Overwhelming victories at Agincourt in 1415 and Verneuil in 1424 as well as an alliance with the Burgundians raised the prospects of an ultimate English triumph and persuaded the English to continue the war over many decades. However, a variety of factors such as the deaths of both Henry and Charles in 1422, the emergence of Joan of Arc which boosted French morale, and the loss of Burgundy as an ally, marking the end of the civil war in France, prevented it.