An Unbreakable Vow is a magical incantation in which one wizard makes an oath to another. If the person who accepts the conditions of the Unbreakable Vow breaks them, they die. The spell involves the two wizards joining their hands, and a third person, designated as a "Bonder", placing the tip of their wand onto their hands, upon which one person gives the other person one or more terms of the Vow, which the other person then agrees to. Upon assent with each clause of an Unbreakable Vow, a thick tongue of fire winds around the linked hands.
(From HarryPotter wikia)
We all are used to rough academical language, in which we get most of the useful (and often not useful) information. But, perhaps, not always should we strain our mind, trying to understand scientific terms and facts. Sometimes, maybe rarely, we need to relax, reading some frank and natural texts, written in an artistic, romantic style, used by prose writers and poets. Quite possibly...
... ...To the most dangerous and complicated conjurations in the history of magic and charms we may add on the Unbreakable Vow, the story which is much darker than we can only imagine. The Unbreakable Vow is thought to be invented by one of the dark wizards in late 1300s in order to gain influence and power. It is interesting to mention that the wizard himself died, breaking the vow, which he gave his wife as a joke. That, of course, may be a legend, but real numbers of the vow's victims may scare even the most composed readers.
15 children
45 women
19 men.
Even though the unbreakable vow was forbidden by the MoM in 1699 it is still very popular in Dark Arts, forcing the number of the dead to grow with each century. At the moment this problem is in the consideration of the Auror office. ...
But more dangerous than a typical unbreakable vow is a double one.
When making a double unbreakable vow, both of the wizards have conditions. The 'Bonder' not needed (unlike in the original unbreakable vow). If one of the wizards breaks the conditions he dies...