A reign is the period of time that a monarch (a king, queen, emperor, etc.) rules over a country. It can also be the period of time that a spiritual leader rules in a particular office. For example, the reign of a pope, dalai lama, patriarch etc. A reign can also be used for an office or championship. In many cases a reign lasts until the monarch (or leader) resigns, dies, or is removed. A monarch's reign was sometimes used to mark time officially. In Anglo-Saxon England for example, many royal documents were dated by the regnal year of the king. This lasted until about the 10th century.