Consensus, non concubitus, facit matrimonium. Co. Litt. 323, (Consent, not cohabitation, constitutes marriage.)
Consent in necessary to matrimony, and therefore person non compotes mentis, or a boy under 14 or a girl under 12, or a person under coercion (see Scott v. Sebright, (1886) 12 PD 21), cannot enter into this, or indeed any other contract. But see now Age of Marriage Act,1929 (19 & 20 Geo. 5, c. 36), which avoids any marriage of persons under 16, and see MARRIAGE.