A group of Royal and Great Seals were examined with C-13 Fourier Transform Nuclear Magnetic Resonance (C-13 FTNMR) spectroscopy to determine the nature of their organic components by comparison with a series of control waxes and resins. While the medieval examples contained only beeswax, the post medieval samples examined contained both wax and the resin colophony. This study showed that until the reign of George III beeswax was used, but then this alternated with other types of wax which may reflect availability of different sources of supply. Whilst colophony is present in all the early modern seals examined, it was noted that differences in colophony spectra between seals may be attributed to variations in source rather than deterioration or oxidation, allowing provenancing of such materials to be developed from this study. -- AATA