The first thing that springs to mind when I think of Henry V is his appearance.
The portrait is a 16th century copy, in it Henry looks as if he is at prayer. He, of course, was regarded as the hero of the nation due to his victory over the French at Agincourt, the battle which saw the English longbow come to the forefront, but also the place where he ordered the deaths of several thousand French prisoners.
The date of Henry's birth is said to be either the 9th or the 16th of August in 1386/7, he was born the second son of Henry IV, he had, by the age of seventeen taken part in the Battle of Shrewsbury and topped that with five years fighting against Welsh and the legendary Owen Glendower, the last Welsh leader to be known as the Prince of Wales. Henry also put down a rebellion lead by Richard of Conisburgh grandfather to Richard III, Henry Scrope and Thomas Grey and their attempt to put Edmund Mortimer on the English throne. This later became known as the Southampton Plot. We also remember King Henry V for his involvement with France where between 1415 and 1420 he was successful in taking the port of Harfleur, the town of Rouen, and managed to force the French to sign the Treaty of Troyes.
Following his success in France, Henry was recognised as the heir to the French throne which was sealed by his marriage to Charles VI's daughter Catherine of Valois. The couple returned home to England, six months later Catherine was crowned queen and two months later, Henry returned to France. The young queen gave birth to her son Henry, later Henry VI, in the December of 1421, but the of hero of Agincourt lay dying from dysentery at the Chateau de Vincennes, in France, where he died on the 31st of August, leaving his lands and titles in the tiny hands of his nine month old son.
If King Henry V had not died that summers day in France, Catherine of Valois would not have been left a young widow to find solace in the arms of Owen Tudor and therefore no there would have been no Henry VII and no Tudor dynasty.
There are two interesting articles on Henry V's achievements one from 1986 by Nigel Saul entitled Henry and the Duel Monarchy and another by Dan Jones entitled From Agincourt to Bosworth, both can be read here.