A new flag to represent the newly…
April 1606 CE
A new flag to represent the newly formed regal union between England and Scotland is specified on April 12, 1606, in a royal decree, according to which the flag of England (a red cross on a white background, known as St. George's Cross), and the flag of Scotland (a white saltire on a blue background, known as the Saltire or St. Andrew's Cross), are to be be joined together, forming the flag of Great Britain and first union flag.
This royal flag is at first only for use at sea on civil and military ships of both England and Scotland, whereas land forces continue to use their respective national banners.
Wales has no explicit recognition in the Union Flag as it has been a part of the Kingdom of England since being annexed by Edward I of England in 1282 and its full integration by the Laws in Wales Acts 1535–1542, and is therefore represented by the flag of England.
The Kingdom of Ireland, which has existed as a personal union with England since 1541, is likewise unrepresented in the original versions of the Union Flag.