History of England
With Henry VII's accession to the throne in 1485, the Wars of the Roses came to an end, and Tudors would continue to rule England for 118 years. Traditionally, the Battle of Bosworth Field is considered to mark the end of the Middle Ages in England, although Henry did not introduce any new concept of monarchy, and for most of his reign his hold on power was tenuous. He claimed the throne by conquest and God's judgement in battle. Parliament quickly recognized him as king, but the Yorkists were far from defeated. Nonetheless, he married Edward IV's eldest daughter Elizabeth in January 1486, thereby uniting the houses of York and Lancaster.
Treaty of Union
Queen Elizabeth I of England and Ireland, last monarch of the Tudor dynasty, died without issue on 24 March 1603, and the throne fell at once (and uncontroversially) to her first cousin twice removed, James VI of Scotland, a member of House of Stuart and the only son of Mary, Queen of Scots. By the Union of the Crowns in 1603 he assumed the throne of the Kingdom of England and the Kingdom of Ireland as King James I. This personal union lessened the constant English fears of Scottish cooperation with France in a feared French invasion of England.