The concept is false!
It is actually based on an 18th century myth, which not only survived until the end of the 20th century both in scientific literature and the literature of popular science, but the collections of major and minor museums also made efforts to provide some relevant data.
The first drawing of a belt was depicted in a book called Bellifortis, written in 1405 by a German military engineer named Konrad Kyeser. Historians have noted that Kyeserโs writing was often comical, and the book included several jokes and references to things that were not meant to be taken literally. With this in mind, itโs possible that the drawing of the belt was another one of his wisecracks placed throughout the book.
It wasnโt until the sixteenth century that references and depictions of chastity belts became commonplace. Even then, the references donโt show the actual usage of the belts. But chastity belts were sometimes worn voluntarily during the Industrial revolution. Many women started working in factories. Due to long shifts, sometimes they had to leave late, which was always dangerous. Quickly growing cities attracted all kinds of people and rape was a considerable threat. By wearing chastity belts some women tried protecting themselves. These chastity belts were made from leather or metal, but they were quite uncomfortable.
In the beginning of the twentieth century the first chastity belts designed to prevent teenagers from masturbating! It was believed that by masturbating children lose their connection to God and indulge in impure thoughts, which is, of course, a sin!
Today chastity belts are more popular than they were at any other point in history. At least, definitely more popular than during Middle ages when they simply didnโt exist.