Six samples of tar and pitch from the wreck of the Mary Rose (Tudor, AD 1509-45) and a sample of pitch from an Etruscan shipwreck (ca. 600 BC) have been analysed by a number of modern analytical techniques (elemental analysis, IR and NMR spectroscopy, GC and GC - MS). Similar analyses were performed on samples of contemporary tars, derived from natural sources, for comparative purposes. The major constituents of the archaeological samples were observed to be alkyl-substituted, tricyclic diterpenoids based on the abietane and pimarane skeletons. Similar molecular compositions and spectral properties were found for Stockholm tar (a good quality wood tar obtained by the destructive distillation of Pinus sylvestris), and Tudor and Etruscan pitches, thus providing conclusive evidence for the derivation of the archaeological samples from pine wood. The analytical techniques utilised are compared for their relative usefulness in chemical archaeology. The analysis of tar and pitch can aid in its conservation. -- CAL