The Succession to the Crown Act 2013 is a law in the United Kingdom that changed the rules of royal succession. It ended the system of male-preference primogeniture, which favored male heirs over female ones. Now, the order of succession is determined by birth order, meaning that the eldest child, regardless of gender, will inherit the throne. Additionally, the Act also removed the disqualification of heirs who marry Catholics. This means that if a royal family member marries a Catholic, they will not lose their right to the throne. These changes modernized the monarchy and made it more inclusive.