Original: The two countries had shared a monarch since the Union of the Crowns in 1603 , when King James VI of Scotland inherited the English throne from his double first cousin twice removed , Queen Elizabeth I. Although described as a Union of Crowns , until 1707 there were in fact two separate Crowns resting on the same head .
Simplified: The two countries had shared a monarch for about 100 years ( since the Union of the Crowns in 1603 , when James VI of Scotland inherited the English throne from his cousin , Queen Elizabeth I ) .