The flag of Great Britain is made up of three of the four flags of the countries that make up the United Kingdom. The four countries in the union are England, Scotland, Wales and Northern Ireland. Ireland, or Eire, is a separate independent country. The three flags that make up the Union Flag or Union Jack, as it is called, are the flags of England, Scotland and Northern Ireland.
The English flag is the flag of St George, the patron saint of the country. It is a red cross on a white background representing purity. It was adopted in the 14th century in the reign of Edward III though St George's flag was used by soldiers going into battle before that. Shakespeare has Henry V rallying his troops at the battle of Agincourt in 1415 by shouting, "Cry God for Harry, England and St George!"
The flag of Scotland is a white diagonal cross on a blue background. This is the cross of St Andrew, Scotland's patron saint, who was martyred on such a cross. The blue represents the sky and the white saltire, or diagonal cross, clouds. The saltire was apparently seen in the sky in 832AD by the Scottish king and his troops before battle.
Northern Ireland's flag
St Patrick is the patron saint of Ireland and the flag used in the Union Flag to represent Northern Ireland is a diagonal red cross on a white background. But St Patrick and St Patrick's Day have always been associated with the colour green, so where did this flag come from? It has been suggested that it was taken from the arms of the premier duke of Ireland, the Duke of Leinster, but there is little contemporary evidence to support this.
Forming of the union
In 1603, the King of Scotland, James VI, became King of England and Scotland on the death of Queen Elizabeth I. Thus the crowns were united and variations combining the two flags were tried out. But it was not until 1801 when St Patrick's flag was added that the present day Union Flag was created. At that time, the whole of Ireland was united and remained part of the United Kingdom until 1921 when the southern part gained independence.
The name Union Jack comes from the flag's use at sea. It was generally flown from the bow of the ship at the jack staff. The Welsh flag has never been included in the Union Flag as Wales had already joined with England before 1606 under the flag of St George. However, the Welsh flag, a red dragon on a green and white background, is commonly flown in Wales.