St George's Day in England remembers St George, England's patron saint. The anniversary of his death, which is on April 23, is seen as England's national day. According to legend, he was a soldier in the Roman army who killed a dragon and saved a princess.
According to legend, St George slayed a dragon. Many Christians observe St George's Day in the UK, although it is not a public holiday.
Many people in England don’t observe nor know when the national day is at all. However, in recent years, celebrating St George's Day seems to gradually be regaining popularity in England. From the 15th century, St George's Day used to be a national holiday in England, and was celebrated as widely as Christmas. But the celebrations waned by the end of the 18th century after England had united with Scotland on May 1, 1707.
http://www.timeanddate.com/holidays/uk/st-george-day