In Britain around 1885 there was a huge public outcry over child prostitution. At that time, the legal age of consent was raised from 13 to 16. Interesting article on it here:
http://www.wickedness.net/els/els1/dcruze paper.pdf
Some time earlier, the Marriage Act of 1753 was passed in England and Wales. This stated that if both parties to a marriage were under the age of 21, then parental consent had to be given for the marriage to take place --- and if it was given, then girls as young as 12 could marry. The age for boys was 14. Prior to that, children could be married to one another as young as age seven, but had to wait until the ages of 12 and 14 to consummate the marriage. The 1753 act came about following a nasty Scottish court case regarding inheritances. Interestingly, when it went into effect in 1754, it did not apply to Scotland.
The law made English marriage laws much stricter, and said that all weddings had to be performed in a church (or a Temple, if you were Jewish) and duly recorded. Any children born to a marriage that was NOT official were considered ineligible to inherit property later on. The result was to put an end to "clandestine" marriages, but a lot of couples managed to get around it by eloping to Scotland and getting married at Gretna Green.
This nifty site here
http://www.umich.edu/~ece/student_projects/wedding_bride/tofc.html looks at the ramifications of the 1753 Act.