A marriage license (or marriage licence in Commonwealth spelling) is a document issued, either by a religious organization or state authority, authorizing a couple to marry. The procedure for obtaining a license varies between jurisdictions, and has changed over time. Marriage licenses began to be issued in the Middle Ages, to permit a marriage which would otherwise be illegal (for instance, if the necessary period of notice for the marriage had not been given). Today, they are a legal requirement in some jurisdictions and may also serve as the record of the marriage itself, if signed by the couple and witnessed. In other jurisdictions, a license is not required. In some jurisdictions, a "pardon" can be obtained for marrying without a license, and in some jurisdictions, common-law marriages and marriage by cohabitation and representation are also recognized. These do not require a marriage license. There are also some jurisdictions where marriage licenses do not exist at all and a marriage certificate is given to the couple after the marriage ceremony has taken place. For most of Western history, marriage was a private contract between two families. Until the 16th century, Christian churches accepted the validity of a marriage on the basis of a couple's declarations. If two people claimed that they had exchanged marital vows, even without witnesses, the Catholic Church accepted that they were validly married. Some states in the US hold that public cohabitation can be sufficient evidence of a valid marriage. Marriage license application records from government authorities are widely available starting from the mid-19th century. Some are available dating from the 17th century in colonial America. Marriage licenses have been required since 1639 in Massachusetts, with their use gradually expanding to other jurisdictions. In Australia, there is no requirement to obtain a marriage license. However, a person under the age of 18 requires the authorisation of a judge to marry.