Marriage describes the legally recognised union of two people, creating a new family unit with rights and obligations in areas such as tax, property, succession, immigration, parental responsibility and financial provision on relationship breakdown or death. In England and Wales, Scotland and Northern Ireland, the core legal framework is set out in marriage legislation (including the Marriage Acts and case law), with same-sex marriage lawful in all three jurisdictions. In Ireland, marriage is governed principally by the Civil Registration and Family Law Acts, with same-sex marriage provided for following the Thirty-Fourth Amendment to the Constitution. Key legal features include formal capacity requirements (age, consent, prohibited degrees of relationship), procedural requirements (notice, authorised celebrant, registration) and the distinction between civil and religious ceremonies. A marriage validly contracted in one jurisdiction may raise private international law questions when recognised in another. Marriage is central to family law practice, underpinning claims for divorce or dissolution, financial remedies, maintenance, pensions sharing, inheritance rights, next-of-kin status and occupation of the family home. It is distinct from civil partnership and cohabitation, which attract different legal consequences.