Was Royal Sovereign the Royal Navy's first first rate?

Which ship was the Royal Navy's first first rate?

Royal Sovereign is probably the best answer, although earlier ships near the category make the identification debatable.

Royal Sovereign is the ship most likely to qualify as the Royal Navy's first first rate. Earlier vessels approached the later category, so the boundary remains debatable. Rating systems developed over time, and applying a later classification backward does not produce a perfectly sharp dividing line. The answer is therefore a qualified starting point.