Found this on another forum
Re: Marriage Legal Age
« Reply #5 on: Thursday 30 November 06 14:36 GMT (UK) »
From time immemorial the age for matrimonial consent was fixed at 7 years, but puberty was accepted as the age for consummation of the marriage, which was 12 for girls and 14 for boys.
Canon 100 of 1603 forbade, but did not invalidate marriage of persons under 21, except with parental consent.
The legal age for marriage from 29 September 1653 was fixed at 16 for a man and 14 for a woman. In 1660 the pre-interregnum laws were reinstated and the ages of marriage reverted to 14 for the groom and 12 for the bride.
Lord Hardwicke's 1753 Marriage Act, made it illegal for those in England under the age of 21 to get married without the consent of their parents or guardians. The consent requirement was repealed and replaced in July 1822, and an act in July1823 restored the pre-1753 rule of Canon 100.
In effect, therefore, from 1823 the age at which a couple could undergo a valid marriage, even without parental consent, reverted to 14 for boys and 12 for girls; although some marriages of younger children still took place.
The 1929 Age of Marriage Act made all marriages void from 10 May 1929, if either partner was under the age of 16.
The legal age for marriage remained at 14 for boys and 12 for girls in the Republic of Ireland, until 1st January 1975, when it was raised to 16.
This is from 'Marriage Laws, Rites, Records & Customs' by Colin R Chapman,
well worth buying.