J.Porteus and T. Kleindinst; Coin courtesy of The American Numismatic Society

The pot shown here contains the only taces found so far of pine tar used to caulk ancient ships. The pot was salvaged in 1989 from th wreck of the Isis, which sank in 2,600 feet of water between Sicily and Tunisia. X-ray analysis of the pot showed a small object embedded in the tar: a copper coin from the reign of Constantius II (c. 355–361 C.E.). This coin dates the wreck of the Isis to the late fourth century C.E.