The choice of law rules which govern the validity of a marriage, and which, therefore, also govern nullity of marriage, depend on the particular issue which is involved. The old rule of English conflict of laws was to the effect that, whatever the ground of invalidity that was alleged, the conclusion of a marriage was a matter for the law of the place where it was celebrated. But since about 1860 this rule has, generally speaking, been confined to questions of formalities of marriage. There now exist several different choice of law rules for marriage, some of which are disputed or difficult to state with full confidence.

Basically, there are four requirements of a valid marriage: (i) that the requisite formalities are complied with; (ii) that the parties have legal capacity to marry each other; (iii) that they freely and knowingly consent to do so; and (iv) that the marriage is consummated.

These will be discussed in turn; the discussion will be followed by an account of the law relating to polygamous marriages.

Formalities of marriage

Formal requirements of a marriage include such matters as whether a religious or a civil ceremony is necessary, whether banns have to be called or notices published and the form of words which must be used. No rule of the conflict of laws is clearer or longer established than the one which lays down that these matters are regulated by the lex loci celebrationis, the law of the place where the ceremony takes place, which reflects the rule locus regit actum.