Muggletonianism were a real thing. And had nothing to do with the "Muggles" of the Harry Potter wizarding world.
In 1651 two London tailors announced that they were the last prophets foretold in the Book of Revelation. And a new Protestant sect was born.
Even though it was John Reeve who believed he received the "word of God" - the movement was named after his cousin Lodowicke Muggleton (pictured left) who joined Reeve in spreading their new Gospel.
If the movement was named after John Reeve I guess his followers would have been known as "Reevers' and would have put my modern mind to thinking of the "Reavers" of the Firefly universe. Whereas Muggletonians really do put your mind to Harry Potter.
Not for nothing but the tenets of Muggletonianism seem pretty reasonable.