After the war with Voldemort the wizarding world was left with questions. Namely, how to prevent a dark lord from ever rising again? To answer this question they looked at another, why had Voldemort become a dark lord? Through the investigation certain facts became common knowledge; Voldemort's real name was Tom Riddle, he was a half-blood, and he had been raised in a muggle orphanage. Due to this information coming to light, some theorized that Tom had become dark due to being orphaned then raised by muggles in a unsavory environment. As politicians will do when trying to come up with an easy fix so they will be reelected, the Minister came up with the idea of a law and since they are Wizards a spell was attached. Unfortunately the witch picked to head up the project had less then a pristine character and as it turned out (or what they claimed later) was a little unstable in the head. They outlined a bill that would in essence create foster homes for children who were magical but orphaned. The magical child would be placed with "a wizarding family of good character." The witch in charge of seeing the project to completion foresaw many difficulties in enforcing the law and making sure the children were in suitable (safe) homes. After all many death eaters had claimed imperious and escaped justice, what if a muggleborn went to a deatheater? Also what if a child was in an abusive environment but not an orphan? So she created two versions of the spell that was to be attached to the law, one simply alerted the ministry when a magical child was orphaned and the other was really quite something. It ensured the when a magical child was orphaned or abused or in an environment where their needs could not be met, that they would be instantly transported and legally adopted by the wizard most able to care for that child. Now to apply this spell she had to do a few illegal acts. One was to make sure it was done in the heart of the ministry and that she was not interrupted when performing the spell. I will spare you the details, but the reporters did get a wonderful story out of the whole experience. The witch had called on deep and old magic cementing the spell in the very foundation of wizarding society and magic. The spell would affect not only the British wizarding society but the whole magical world. There is always a cost to this much power being used and the witch died. With her death any possibility of removing the spell disappeared and her unintended sacrifice increased and strengthened the spell.
Almost a year after the war Severus Tobias Snape received the first of the five raven haired little boys that would become his children. The first boy to arrived was Sherlock Homes.