Numbering the Kings and Queens of Britain

From Royal Central:

One aspect of the evolution of monarchy that I find interesting is the development of Ordinal numbers, or regnal numbers, and also called post-nominal numbers used to differentiate between monarchs of the same name within the same territory. In the British system of numbering the monarchs, a king or queen will not get a regnal number unless there is another monarch with the same name. For example, King John of England (1199-1217) (known as John Lackland) isn’t called John I because there has never been another King John. If there is another King John, he will be John II while John Lackland will become John I.

The practice of ascribing a regnal number to the sovereign was a later development with each monarchy in Europe having its own rules and practices. However, there were times this practice wasn’t always accurate. In this article, I will focus on the numbering of the Kings and Queen of Britain.

Prior to the development of regnal numbers, contemporary monarchs were known by either their territorial designations or a sobriquet, a nickname, that developed over time. An example of a territorial designation is Henry III of England (1217-1272) who was also known as Henry of Winchester during his 50-year reign. Generally, a sobriquet was given by others. For instance, William I of England (1066-1087) is more well known as William the Conqueror but prior to having that sobriquet, he was known as William the Bastard due to his illegitimacy. (Read more.)