Sir David further extended the castle in the late 16th century, with the addition of a large north range with round corner towers. He laid out the garden in 1604, with symbols of England, Scotland and Ireland, to celebrate the Union of the Crowns of the previous year, when James VI acceded to the English throne on the death of his cousin, Elizabeth I. Sir David died in 1610, heavily in debt as a result of fines handed down for the unruly conduct of his son, and with both the garden and the north range incomplete.