such as Strabo, Pausanias, Diodorus Siculus, etc. Traces of customs, creeds, rituals, etc.: In the Aegean area at a later time, discordant with the civilization in which they were practiced and indicating survival from earlier systems. There are also possible linguistic and even physical survivals to be considered. Mycenae and Tiryns are the two principal sites on which evidence of a prehistoric civilization was remarked long ago by the ancient Greeks. Discovery The curtain-wall and towers of the Mycenaean citadel, its gate with heraldic lions, and the great "Treasury of Atreus" had borne silent witness for ages before Heinrich Schliemann's time. However, they were regarded as a crude precursor of later Greek culture. It was not until Schliemann's excavations that Mycenaean culture attracted serious scholarly attention. There had been, however, a good deal of other evidence available before 1876, which, had it been collated and seriously studied, might have discounted the sensation that the discovery of the citadel graves eventually made. For instance, scholars had noted that tributaries appearing in Egyptian art resembled modern Greeks, but were unable to definitely recognize them as such. Nor did the Aegean objects which were lying obscurely in museums in 1870, or thereabouts, provide a sufficient test of the real basis underlying the Hellenic myths of the Argolid, the Troad and Crete, to cause these to be taken seriously. Aegean vases have been exhibited both at Sèvres and Neuchatel since about 1840, the provenance (i.e. source or origin) being in the one case Phylakope in Melos, in the other Cephalonia. Ludwig Ross, the German archaeologist appointed Curator of the Antiquities of Athens at the time of the establishment of the Kingdom of Greece, by his explorations in the Greek islands from 1835 onwards, called attention to certain early intaglios, since known as Inselsteine; but it was not until 1878 that C. T. Newton demonstrated these to be no strayed Phoenician products. In 1866 primitive structures were discovered on the island of Therasia by quarrymen extracting pozzolana, a siliceous volcanic ash, for the Suez Canal works. When this discovery was followed up in 1870, on the neighbouring Santorini (Thera), by representatives of the French School at Athens, much pottery of a class now known immediately to precede the typical late Aegean ware, and many stone and metal objects, were found. These were dated by the geologist Ferdinand A. Fouqué, somewhat arbitrarily, to 2000 BC, by