Saint George was officially canonized by Pope Gelasius in 494 A.D., but by then, he was a semi-mythical figure whose real life was shrouded in mystery. The pope's canonization statement characterized George as a saint whose name is known to all, but whose deeds were known only to God.
The martyrdom of Saint George occurred on April 23, 303. He was a soldier for the emperor Diocletian, who passed an edict that all Christian soldiers in his army should be arrested or forced to honor the gods of Rome. George was a good friend of Diocletian, but he refused to renounce his faith. After George made multiple public refusals that enraged and embarrassed the emperor, Diocletian had him tortured and beheaded. His suffering was said to have inspired the empress to convert to Christianity on the spot, and she was martyred as well.
The most famous story of Saint George is his slaying of the dragon. A dragon took up residence at the spring that fed a nearby city, and the citizens took to drawing lots to provide it with a maiden in order to collect water. When the name of the princess was drawn, the king begged for her release, but the citizens refused. Saint George heard the monarch's plea and rode out to face the dragon, protecting himself with the sign of the cross and defeating the beast. The grateful city converted from their pagan beliefs to Christianity after witnessing George's bravery.