Boiled down to essentials, the couple publicly make certain statements, or publicly assent to certain statements made by another, often called "vows", which result in a legally binding marital relationship. The vows can take many forms, for example:
Historically (i.e. a long time ago), legal scholars noted the following legal principles pertaining to the estate of marriage:
1. Marriage is a contract made in due form of law, by which a free man and a free woman reciprocally engage to live with each other during their joint lives, in the union which ought to exist between husband and wife. By the terms freeman and freewoman in this definition are meant, not only that they are free and not slaves, but also that they are clear of all bars to a lawful marriage. Dig. 23, 2, 1; Ayl. Parer. 359; Stair, Inst. tit. 4, s. 1; Shelford on Mar. and Div. c. 1, s. 1.
2. To make a valid marriage, the parties must be willing to contract, able to contract, and have actually contracted.
3. They must be willing to contract. Those persons, therefore, who have no legal capacity in point of intellect, to make a contract, cannot legally marry, as idiots, lunatics, and infants, males under the age of fourteen, and females under the age of twelve, and when minors over those ages marry, they must have the consent of their parents or guardians.
4. There is no will when the person is mistaken in the party whom he intended to marry; as, if Peter intending to marry Maria, through error or mistake of person, in fact marries Eliza; but an error in the fortune, as if a man marries a woman whom he believes to be rich, and he finds her to be poor; or in the quality, as if he marry a woman whom he took to be chaste, and whom he finds of an opposite character, this does not invalidate the marriage, because in these cases the error is only of some quality or accident, and not in the person. Poynt. on Marr. and Div. ch. 9.
5. When the marriage is obtained by force or fraud, it is clear that there is no consent; it is, therefore, void ab initio, and may be treated as null by every court in which its validity may incidentally be called in question. 2 Kent, Com. 66; Shelf. on Marr. and Div. 199; 2 Hagg. Cons. R. 246; 5 Paige, 43.
6. Generally, all persons who are of sound mind, and have arrived to years of maturity, are able to contract marriage. To this general rule, however, there are many exceptions, among which the following may be enumerated:
7. The parties must not only be willing and able, but must have actually contracted in due form of law.
8. The common law requires no particular ceremony to the valid celebration of marriage. The consent of the parties is all that is necessary, and as marriage is said to be a contract jure gentium, that consent is all that is needful by natural or public law. If the contract be made per verba de presenti, or if made per verba de futuro, and followed by consummation, it amounts to a valid marriage, and which the parties cannot dissolve, if otherwise competent. It is not necessary that a clergyman should be present to give validity to the marriage; the consent of the parties may be declared before a magistrate, or simply before witnesses; or subsequently confessed or acknowledged, or the marriage may even be inferred from continual cohabitation, and reputation as husband and wife, except in cases of civil actions for adultery, or public prosecutions for bigamy. 1 Silk. 119; 4 Burr. 2057; Dougl. 171; Burr. Settl. Cas. 509; 1 Dow, 148; 2 Dow, 482; 4 John. 2; 18 John. R. 346; 6 Binn, 405; 1 Penn. R. 452; 2 Watts, R. 9. But a promise to marry at a future time, cannot, by any process of law, be converted into a marriage, though the breach of such promise will be the foundation of an action for damages.
9. In some of the states, statutory regulations have been made on this subject. In Maine and Massachusetts, the marriage must be made in the presence, and with the assent of a magistrate, or a stated or ordained minister of the gospel. 7 Mass. Rep. 48; 2 Greenl. Rep. 102. The statute of Connecticut on this subject, requires the marriage to be celebrated by a clergyman or magistrate, and requires the previous publication of the intention of marriage, and the consent of parents; it inflicts a penalty on those who disobey its regulations. The marriage, however, would probably be considered valid, although the regulations of the statutes had not been observed. Reeve’s Dom. Rel. 196, 200, 290. The rule in Pennsylvania is, that the marriage is valid, although the directions of the statute have not been observed. 2 Watts, Rep. 9; 1 How. S. C. R. 219. The same rule probably obtains in New Jersey; 2 Halsted, 138; New Hampshire; 2 N. H. Rep. 268; and Kentucky. 3 Marsh. R. 370. In Louisiana, a license must be obtained from the parish judge of the parish in which at least one of the parties is domiciliated, and the marriage must be celebrated before a priest or minister of a religious sect, or an authorized justice of the peace; it must be celebrated in the presence of three witnesses of full age, and an act must be made of the celebration, signed by the person who celebrated the marriage, by the parties and the witnesses. Code, art. 101 to 107. The 89th article of the Code declares, that such marriages only are recognized by law, as are contracted and solemnized according to the rules which it prescribes. But the Code does not declare null a marriage not preceded by a license, and not evidenced by an act signed by a certain number of witnesses and the parties, nor does it make such an act exclusive evidence of the marriage. The laws relating to forms and ceremonies are directory to those who are authorized to celebrate marriage. 6 L. R. 470.
10. A marriage made in a foreign country, if good there, would, in general, be held good in this country, unless when it would work injustice, or be contra bonos mores, or be repugnant to the settled principles and policy of our laws. Story, Confl. of Laws, Sec. 87; Shelf. on M. & D. 140; 1 Bland. 188; 2 Bland. 485; 3 John. Ch. R. 190; 8 Ala. R. 48.
11. Marriage is a contract intended in its origin to endure till the death of one of the contracting parties. It is dissolved by death or divorce.
12. In some cases, as in prosecutions for bigamy, by the common law, an actual marriage must be proved in order to convict the accused. See 6 Conn. R. 446. This rule is much qualified. See Bigamy.
13. But for many purposes it may be proved by circumstances; for example, cohabitation; acknowledgment by the parties themselves that they were married; their reception as such by their friends and relations; their correspondence, on being casually separated, addressing each other as man and wife; 2 Bl. R. 899; declaring, deliberately, that the marriage took place in a foreign country; 2 Moo. & R. 503; describing their children, in parish registers of baptism, as their legitimate offspring; 2 Str. 1073; 8 Ves. 417; or when the parties pass for husband and wife by common reputation. 1 Bl. R. 639; S. C. 4 Burr. 2057; Dougl. 174; Cowp. 594; 3 Swans. R. 400; 8 S. & R. 159; 2 Hayw. R. 3; 1 Taylor, R. 121; 1 H. & McH. 152; 2 N. & McC. 114; 5 Day, R. 290; 4 R. & M. 507; 9 Mass. R. 414; 4 John. 52; 18 John. 346. After their death, the presumption is generally conclusive. Cowp. 591; 6 T. R. 330.
14. The civil effects of marriage are the following:
15. Generally, the law does not recognize marriage between cats.