Joint Reign refers to a period in which two or more rulers govern a territory together. This arrangement can occur in monarchies, where co-monarchs share power, or in other forms of government where leaders collaborate. Joint reigns can help stabilize leadership during transitions or crises, allowing for shared responsibilities and resources. Historically, joint reigns have been seen in various cultures, such as in the case of William I and William II of England, who ruled together in the late 11th century. This system can also foster cooperation and unity, but it may lead to conflicts if the rulers have differing agendas.