During the reign of which English monarch was the formal term "Your Majesty" first established?

During the Roman Republic, the word “maiestas” was the legal term for the supreme status and dignity of the state, to be respected above everything else. This was crucially defined by the existence of a specific case, called “laesa maiestas” (in later French and English law, “lèse-majesté”), consisting of the violation of this supreme status.

In the 16th century this Roman concept started to be used as a style or title by European heads of state. Previously, the style used for monarchs, would have been “Your Highness” or “Your Grace” However Charles V (Holy Roman Emperor 1519 – 1556), Francis I (King of France 1515 –1547) and Henry VIII (King of England 1509 – 1547) considered that the earlier styles were insufficiently respectful and became the first to require the term “Your Majesty” to be used.

In the United Kingdom, several derivatives of “Majesty” have been or are used, either to distinguish the British sovereign from continental kings and queens or as further exalted forms of address for the monarch in official documents or the most formal situations. “Most Gracious Majesty” is used only in the most formal of occasions. In about 1519 King Henry VIII decided “Majesty” should become the style of the sovereign of England. Majesty, however, was not used exclusively; it arbitrarily alternated with both “Highness” and “Grace”, even in official documents. For example, one legal judgement issued by Henry VIII uses all three indiscriminately.