He is described by Giovanni Baglione as possessing a collection, a wunderkammer of bellissime bizzarrie ("beautiful bizarre objects"), including among the objects exotic weaponry; fossilized plants; tiger, lion, and turtle skulls; oriental porcelain and sculpted crockery; a vest made of human skin; a harness for dragging whales on ice; a three-legged flea, Persian uniforms, and antiquities such as Roman coins, bronze lamps, and a few statuettes.
After Napoletano's death at Rome in 1628, bidding for such material was made by collectors such as Cardinal Ippolito Aldobrandini (future Clement VIII) and Cassiano dal Pozzo.