Gilles de Rais (also spelled Retz) (autumn of 1404 – October 26, 1440) was a French noble, soldier, and one time brother-in-arms of Joan of Arc. He was later accused and ultimately convicted of infanticide - torturing, raping and murdering dozens, if not hundreds, of children. Along with Erzsébet Báthory, another sadistic aristocrat acting more than a century later, he is considered by some historians to be a precursor of the modern serial killer.

Gilles de Rais was born in 1404 in the château of Machécoul, near the border of Brittany. His father was Guy de Montmorency-Laval, from the house of Laval who had inherited, via adoption, the fortunes of Jeanne de Rais and Marie de Craon.

His father died when he was nine, and his mother immediately married again and abandoned her two children to die two years later c.1415. Gilles and his brother René must have felt alone in the world.

Their father's will made provision for them to be brought up by a cousin and educated by two priests; instead they were sent to live with their grandfather, Jean de Craon, who had a violent temper, but was too wrapped up in his own affairs to pay attention to his grandsons. His own son had been killed at the battle of Agincourt in 1415, so that Gilles became heir to the entire vast fortune. He was an intelligent child who read Latin fluently and loved music. Gilles came from a family of medieval knights, so he was trained in the art if war and chivalry..

He already had a taste for the "forbidden" and secretly devoured Suetonius, with his details of the sexual excesses of the Roman emperors.

Five years later, he went to the court of the Dauphin, the uncrowned heir to the throne, and made a considerable impression with his good looks and fine breeding.

Jean de Craon sought to marry Gilles off to the heiress Jeanne de Paynol; this was unsuccessful. Jean de Craon then attempted to join de Rais with Beatrice de Rohan, niece of the Duke of Brittany, again with no success. Eventually he was able to substantially increase Rais's fortune by marrying him off to Catherine de Thouars of Brittany, heiress of La Vendee and Poitou, but only after first kidnapping her.

Later stories connecting Rais with the legendary wife-murderer Bluebeard may have stemmed from the fact that two of several previous marriage schemes were thwarted by the death of the intended bride. By his marriage to the extremely wealthy heiress, Gilles de Rais became one of the richest noble in Europe, From 1427 to 1435, Rais served as a commander in the Royal Army,