What Is a Duke? Here's Everything We Know About the Royal Title

Prince. Duke. Earl. Baron. There are a variety of titles men in the monarchy can be given these days. And, if we’re being completely honest, it can be difficult to keep track of the differences between them. We know Prince William (now Prince of Wales) was previously granted the titles of Duke of Cornwall and Cambridge, and Prince Harry is also the Duke of Sussex. But what makes William and Harry dukes? And what is a duke? 

First, it’s important to know that there are five possible titles for males in the peerage system (a legal system conferring titles of realms in the United Kingdom). Ranked from highest to lowest, they include duke, marquess, earl, viscount and baron.

A duke is the member of nobility that ranks directly below the monarch. It means the individual is a ruler of the “duchy” (a county, territory or domain).

The title can either be passed down by a parent (aka inherited) or given as a title by a king or queen. It's also a tradition for men of the royal family to get a new title when they marry. For example, Prince William became the Duke of Cambridge when he married Kate Middleton in 2011, granting her the title of Duchess of Cambridge. Prince Harry became the Duke of Sussex after tying the knot with Meghan Markle, also making her his duchess. 

However, King Charles became the Duke of Cornwall at just 4 years old when the title was bestowed on him by the queen (the title later passed to William upon the queen's death).