So, if you follow the news you may have noticed that Scotland recently passed marriage equality, which means the legendary Gretna Green might be getting some more business in a few months! And this got me thinking about the phrase "married over the anvil" and I found this kitchy video which you might enjoy. I also found a claim that this practice was only an expression and didn't actually happen.
Now, some idioms about marriage ("tying the knot" and "jumping the broom" come to mind) come from real practices, and since iron lore is such a big thing in cultures, this one seems pretty plausible to me. But I can't find anything concrete either way!
So, did people actually hold hands over the anvil and pledge their troth when they ran away to Gretna Green in the 18th century?
The Marriage Act of 1754 made it illegal to marry without parental consent if you were under the age of 21 (previously it had been 16), and required marriages to take place within a church, where the banns are read for three Sundays preceding the ceremony - so there's no scope for eloping. Scotland refused to pass the law and so Gretna became the first port of call for eloping couples - in Scotland handfasting and marriage by declaration (announcing your wish to be husband and wife in front of two witnesses) were legal until 1940.
Joseph Paisley, the original blacksmith at Gretna Green was a bit of a showman and was happy to marry people in exchange for a drink or a few guineas (suspect he made his call based on how prosperous the couple appeared?). He'd bring his hammer down onto the anvil to signify that the marriage was complete and say something about forging two metals together to seal the romance.
Crucially for eloping couples sneaking over the border by night, his shop was at the centre of five coaching routes and he also kept "doctor's hours", meaning that he was happy to go to work whenever someone knocked on his door so they'd be safely married without having to wait until the morning (edit: and risk that whoever was against the marriage would catch up to them before they'd completed the deed).
So marrying over the anvil was a real thing, originally for practical reasons (who else is going to get out of bed and marry you at 2am?) but it turned romantic because of the showmanship of the smith.
Try Gretna Green: A Romantic History by [someone, Olive? Olga? Olivia?] Sinclair.