A purple sediment on the inside surfaces of potsherds from the Late Bronze Age of Sarepta, in the Lebanon, was shown to contain 6, 6'-dibromoindigotin, a purple dye obtained from certain shellfish by the early phoenicians. proton-induced x-ray emission spectroscopy (PIXE) showed the presence of bromime, electron spectroscopic chemical analysis (ESCA) confirmed organic bromine and indicated carbonyl and hydrocarbon carbon and unoxidized nitrogen, and diffuse reflectance Fourier transform infrared spectroscopy produced a spectrum consistent with that from the synthetic compound. The identity was confirmed by reduction with sodium hydrosulfite. This is the earliest identification so far of this dye; possible mollusc sources for it are discussed. -- AATA