from Fancyclopedia 2 ca. 1959
A slanshack on Cooper Square, New York, occupied by Bill Donaho, Art Saha, and a mort o' transients. It was the scene of several parties, including the Fanarcon.

from Fancyclopedia 2 Supplement ca. 1960:
Art Saha never lived there. Its first fanhabitant was Dan Curran, who followed the three girls who originally lived there and gave the place its name. When the last of these moved out, Donaho moved in, and this pair were the "proprietors" of the Nunnery thenceforth.