I am reading the epistle to a 1603 edition translation of the Morals of Plutarch. In the epistle, it reads:
"To the Most High and Mighty Prince, James, by the Grace of God, King of England, Scotland and Ireland, Defender of the Faith, &c."
I'm confused by a number of things in this. First he is referred to as both prince and king. Is this because he wasn't coronated yet at this point?
Also, he is listed as the king of several regions. First, France? What gives? As for the rest, I understand Scotland, since he inherited it from his mother, but what about the rest? It wasn't unified until later (I think around 1607?).
Thanks for your insight in advance!
While "prince" today is widely used to mean "heir to the throne", for most of European history, "prince" confusingly just meant, essentially, a noble who owed no direct allegiance to a higher ranked noble. In England and Scotland, the prince was a king; but in Austria, for instance, the prince was the Archduke, while other princedoms in the Holy Roman Emperor were led by Counts, Dukes, Electors, Margraves, and other various titles.
The various titles:
James was the first monarch to hold all of the territories that we call "Great Britain", and indeed called himself "King of Great Britain". However, Scotland's government remained separate from England's until the Act of Union 1707 (you were close!), which formally combined the two governments after over a century (Cromwell's rule excepted) of what is called a "personal union". Prior to that point, the two kingdoms were separated politically besides their shared monarch.
As for "King of France", the English claimed the French throne from the beginning of the Hundred Years War in the 1300s until some time after the French Revolution in 1789. Even though England lost virtually all of its Continental territory by the end of the fifteenth century, the English monarchs still maintained that they were the rightful monarchs of France.
English claims over Ireland trace back to the Norman period (the 12th and 13th centuries). However, until King Henry VIII of England was crowed "King of Ireland" and moved to conquer the island, English control was virtually non-existent. King James, for his part, was responsible for greatly enhancing the speed of the Plantations in Ireland, which displaced the native Catholic Irish with Protestant English and Scottish settlers.
King Henry VIII received the title of "Defender of the Faith" from the Pope in 1521, after the King published a vigorous defense of Catholicism against the criticisms of the early Protestants. When Henry himself broke away from the Catholic Church during the 1530s, he kept the title and Parliament declared that he and his successors would carry it. The title effectively refers to the English monarch's position as head of the Anglican church.
A good introductory work for all of this is Early Modern England 1485-1714: A Narrative History, 2nd Edition, by Robert Bucholz and Newton Key. Let me know if you have any other questions.