Okay, I have used this as a plot point of a couple of my Regency romances, most notably in Lady Chandler’s Sister and A Dance with Mr. Darcy, but in each book, the actual marriage did not occur with a handfasting situation.
Basically, it is hard to find evidence that the ceremony called handfasting ever existed. Some do say it was something that was practiced in earlier earlier days in remote sections of Scotland. Others say it is just a sort of “myth” or confused with old style of betrothal.
In some accounts the hands of the man and woman are bound together with some sort of scarf or ribbon. In others, they hold hands and make a declaration that they were hand fasted.
This was actually the equivalent of a very “public affair” for a year. The couple announced they were essentially doing what modern times call “shacking up.” At the end of the year or anytime before that, the couple can separate and go handfast with another or marry another.
However, the couple were considered firmly married if the woman became pregnant.
A couple of things are wrong with this:
Scotland had marriage by declaration. If two people claimed they were married and lived together as married, they were considered married and required a divorce to marry another. You will read something similar in the last book of my Dragonblade mystery series, Lyon on the Inside, but with a slight twist.
Most of the Scots disapproved of couples living together outside of marriage. They disapproved of marriage by declaration and wanted banns and a church service and disliked the casual marriage by declaration of a “Over the Anvil” priest.
There is nothing at all in the laws of Scotland or England to make one believe either country or church would tolerate such a temporary situation.
I think the idea of living together for a year-and-a-day came from the law that said a woman had to be married for a year and a day in order to be considered as a “widow” if the husband died— that is, unless, a child was born.
Anyway, an author can have a man and woman meeting up again after some years. Then the story gets complicated. The couple can say they were hand fasted. Well if they were handfasted, the child made it a marriage, and they were married so the child was legitimate. If they were not married in Scotland—even if they later marry, the child is illegitimate. If they aren’t married because they were not really handfasted, then they have to marry in Scotland and the boy can be legitimate.
As I don’t believe hand fasting existed then, the child is illegitimate. If the child were born in Scotland and the couple marry in Scotland, the law there allows the child to be legitimate.
I know this explanation is probably more confusing than clarifying. Part of that is due, I claim, to the fact that the the author had some parts of handfasting process wrong. Even if it never existed, the points of action about it should be correct.
Handfasting could not work if the couple is marrying in England. There are varying views on Handfasting. Definitely it is a Scottish “tradition” and not an English one. Some say the union is consummated and some say not.
Sir Walter Scott described it as “When we are handfasted, as we term it, we are man and wife for a year and a day; that space gone by, each may choose another mate, or, at their pleasure, may call the priest to marry them for life; and this we call handfasting.”
Sir Walter Scott did do research into practices of Scotland and write about them, but he was looking more for romantical items. He presented a romantical (ROMANCE ERA POETS) view of history. Historians cannot find that handfasting took place in lowlands or were considered legal. To me, hat makes sense, especially the highland/lowland difference. The Highlanders held to their Celtic roots, while lowlanders eased towards the same practices as the English. Of course, I have to defend that the highlanders handfasted in the 13th Century and not all the way to the 19th Century. Helps, though, that there is so little research at the time. Fictional license helps too, but only if the readers allow/accept it.
There was no need for the handfasting if the couple did not live together as man and wife and no need to say that the union became a marriage if a child was conceived if the marriage was not consummated. It does appear sometimes that those who who did not like irregular marriages accepting handfasting.
In any event, often in a book I am reading that has a handfasting scene, my head swims not because the act may never had existed, but all the restrictions the author places on it. That is my complaint, not so much as that the author had a couple who had been handfasted years before, but stick to the “accepted” rules of the tale.
**The other thing is that the handfasting took place between two people of the aristocracy around the 19th century. The 13th century was an entirely different place.
There is enough material suggesting that someone practiced it to make it legitimate for a novelist.
“Without clear instructions Francis Lewis and the other members of the New York delegation were compelled to abstain from the votes for independence on July 2 and the Declaration of Independence on July 4. Both votes were carried by a unanimous vote of the other colonies, 12 to 0. Within a few days the New York delegation received authorization to join with the other 12 colonies, and on August 2, Francis Lewis joined with most of the other delegates of Congress and signed the Declaration of Independence. 
(Memorial to Francis Lewis at Trinity Church Cemetery, New York City, Wikipedia) “Lewis retired from public service in 1781. He served for a time as vestryman of Trinity Church from 1784-1786. The old age of Francis Lewis was happy and cheerful–literature was an unfailing resource, and he enjoyed the society of his children and grandchildren, who provided him with much amusement. Twenty one years after his retirement, Lewis died on December 31, 1802, at the age of 89. He was buried in an unmarked grave in the churchyard of Trinity Church, one of New York City’s oldest and most famous Episcopal churches. A granite marker and bronze plaque were installed there in his memory in 1947 by the Descendants of the Signers of the Declaration of Independence.” 
(Governor Stephens Hopkins House, 15 Hopkins Street, Providence, via 
( image via 
The signature of Mr. Hopkins is remarkable, and appears as if written by one greatly agitated by fear. But fea was no part of Mr. Hopkins’ character. The cause of the tremulous appearance of his signature, was a bodily infirmity, called “shaking palsy,” with which he had been afflicted many years, and which obliged him to employ an amanuensis to do his writing… (
Every Woman Dreams... 