Today, April 23rd, is the day Christian churches around the world commemorate the memory of St. George who was martyred on this date in 303 AD, in Nicomedia (the then Imperial capital).
I won’t relate the entire story of his life, martyrdom and the legend with the slaying of the dragon. You can read all that on such places as Wikipedia:
However, I will go over the heraldic influence of the Saint – it has been enormous!
Below is a short sampling of arms with the with either St. George’s cross or the Saint himelf:
You can view a lot more on Wikimedia Commons at these locations: