Upon seeing the skeleton in the cave, he was immediately drawn to the ring on its hand.
Boas instantly determined that it was a magic ring.
Although the ring was styled like one from the 15th century, the Latin inscription inside, Vivian A, convinced Boas of its owner's identity.
Legend has it that Merlin was trapped on an island by a beautiful wizard named Vivian, to whom Merlin was entirely obedient.
Vivian was, of course, the beautiful witch, and the A stood for Merlin's surname, Ambrosius.
Clearly, Vivian married Merlin.
As for why a person from the year 500 AD would possess a 15th-century-style ring,
Boas believed that Merlin and Vivian had mastered the magic of time travel, or perhaps they simply lived that long thanks to their strong life force. If the latter were true, the skeleton in the cave might belong to someone who accidentally stumbled onto the island where Vivian and Merlin lived and stole Vivian's enchanted ring.
