I love seeing James the VI and I because so many Englishmen fixate on James I and forget he was sixth of that ilk in Scotland. My school in Edinburgh was founded by his wife's jeweller Jinglin' Geordie, he held the royal (gambling and other) debts.
Less fortunately for Scotland perhaps, the Scots crown diminished from this point on. Money moved south with the king, the Darien Scheme destroyed the scots economy and "the parcel of rogues" agreed to sell the debt to England in the Union. Long after James VI & I of course.
Charles I fixation with divine right of kings must stem from this work. So the English revolution and Cromwell also lies in the bones of his book. Maybe he should have stuck to poetry. Lovely to have his manuscript writing.