Less than a year after an Apache family sued Skull and Bones to recover the remains of its famous ancestor, what appears to be another skull with ties to the notorious secret society is up for auction at Christie’s, the Associated Press is reporting.

The skull will be auctioned off Jan. 22 for a bounty Christie’s estimates will fall between $10,000 and $20,000. Although the current owner and seller has (aptly, perhaps) opted to conceal his identity — Christie’s described him as a “European art collector” — the artifact was supposedly once owned by Bonesman Edward T. Owen 1872, a French and linguistics professor at the University of Wisconsin.

Not just any skeletal head, this skull is modified with a hinged flap and may once have been used as a ballot box during voting at Bones meetings, according to the listing on the Christie’s Web site. The artifact also bears a mysterious etching: the word “THOR,” perhaps a long-forgotten nickname.

The skull will be accompanied on the auction block by a black book containing the names and photographs of roughly 50 Bonesmen, including former President William Howard Taft 1878. The book is inscribed with Owen’s name, the year 1872 and the number 322, which also appears in the society’s emblem.

The bidding starts Jan. 21 in New York’s Rockefeller Center.