The most famous soldier-saint is St. George. At the same time, St. George's story is the most mythical of all saints. Dragons are not real, after all. Nonetheless, St. George is a popular patron of soldiers. During the height of Russian intervention in Syria, an image circulated the Orthodox internet of St. George slaying a dragon, with the flag of ISIS superimposed upon the outline of the dragon, while the Order of St. George is the highest military decoration of the Russian Federation.
St. George may have been a soldier, but in truth nothing is really known about the saint. As Jim Forest writes,
The real Saint George never saw a dragon nor did he rescue a princess in distress. We are not even sure he had a horse or possessed a lance or sword. It is even possible he was a farmer. The name “George” means tiller of the soil. For this reason Saint George is a patron saint of agriculture, herds, flocks and shepherds.…
In icons made in the centuries before the legend of the dragon became attached to George’s name, we see him dressed as a soldier and holding the cross of martyrdom.
Perhaps he was in the army, but it may be that George is shown in military gear because he so perfectly exemplifies the qualities that Saint Paul spoke of in his letter to the Ephesians in which he calls on Christ’s followers to wear the helmet of salvation and the armor of righteousness, to be girded with truth, to clad their feet in the Gospel of peace, to possess the sword of the Spirit which is the word of God, and to protect themselves from the devil’s flaming arrows with the shield of faith.
Whether he was a soldier or not, St. George is remembered for his martyrdom, and not his military accomplishments (of which none are known).
Given that dragons are obviously fictional, one cannot speak of St. George without mentioning symbolism. The dragon he slew has been variously interpreted as real enemies of the state, ideological enemies of Christianity, or the passions which afflict the soul. However, if we take the most famous version of the story of St. George and the Dragon, the Golden Legend, the dragon takes on an altogether different meaning.
Jim Forest summarizes this account,
It was only in later centuries that the dragon legend emerged. It has been told in many variations, but in its most popular form it concerns a dragon living in a lake who was worshiped by the unbaptized local people who, in their fear, sacrificed their children to appease the creature. Finally it was the turn of the king’s daughter, Elizabeth, to be sacrificed. While she was going toward the dragon to meet her doom, George appeared riding a white horse. He prayed to the Father, Son and Holy Spirit, then transfixed the dragon with his lance. Afterward Elizabeth led the vanquished creature into the city.
According to the Legenda Aurea written by Blessed James de Voragine about 1260, the wounded monster followed Elizabeth “as if it had been a meek beast and debonair.” Refusing a reward of treasure, George called on the local people to be baptized. The king agreed, also promising to maintain churches, honor the clergy, faithfully attend religious services and show compassion to the poor.
In this version of the story, St. George does end up killing the beast at the insistence of the town. It is notable, however, that this does not appear to be St. George's original intention. Rather he tames the dragon and leads it by a leash into the town, offering peace between these old enemies. Even in the legend, St. George is more of a peacemaker than a soldier.