What is the history and background of England's map caption or brief summary about England's map?

The United Kingdom is the unification of England, Scotland, Ireland and Wales. The English flag is the flag of St. George, a red cross on a white background. The Scottish flag is the flag of St. Andrew, a diagonal white cross on a blue background. The Irish flag is the flag of St. Patrick, a diagonal red cross on a white background. Wales was already part of England at the time of the formation of the United Kingdom, so there was no Welsh flag to incorporate. If you look at the Union Jack, you'll see all three crosses superimposed on each other.