- "Then came the fateful day when Blagdon Blay, a wizard who had been burgled 19 times in two weeks , succeeded in inventing an Anti-Alohomora Charm. In a single night, the wizarding doors of London were sealed shut, and task-forces were dispatched to protect Muggle houses, too."
- —Miranda Goshawk, Book of Spells.[src]
Blagdon Blay (fl. early 1600s) was a wizard and a Londoner in the early 17th century who was responsible for the creation of the Anti-Alohomora Charm — effectively stopping a series of burglaries by wizards using the then-innovative Unlocking Charm.
When thief Eldon Elsrickle introduced the Unlocking Spell (which he had learnt from an ancient African sorcerer) to London, there was an unprecedented series of recurring burglaries and break-ins by unscrupulous wizards, upon the homes of Muggles and fellow wizards alike.
Blagdon Blay had his house broken into nineteen times in the course of just two weeks. He managed to develop an Anti-Alohomora Charm to secure his house, and soon all the London wizards sealed their houses shut at night, and special wizard task-forces protected those of Muggles.
- Wonderbook: Book of Spells (First appearance)