Reign is he period during which a king or queen occupies the throne (or rules).
Queen elizibeth
The house of Hanover in 1714, when George I came to the throne.
Tudor!!!!!! He so ruled during this period!!!!
Prince Charles
George V
In "The Throne of Fire" by Rick Riordan, Carter and Zia share a close bond, but their relationship doesn't develop into a romantic one during the course of the story. They continue to work together as allies and friends to achieve their goals.
George V was on the throne at the first Commonwealth Games in 1930.
For them he was considered a usurper of the Bourbon throne.
Prince William
Britain or United Kingdom.
You need to specify which particular country you mean: Spain? Sicily? Egypt? Germany? Scotland? You also need to specify what years you are interested in. The medieval period lasted for about a thousand years, any one country (if it had been able to last that long) would have had many kings on the throne.