Often historians assume, as a general rule, that autochthonous inhabitants survive an invasion as an under-class where they do not retreat to mountain districts, so it is interesting to hear in "Deipnosophistae" that Philippus of Theangela (a 4th-century BC historian) referred to "Leleges" still surviving as serfs of the "true Carians", and even later Strabo attributes to the "Leleges" a distinctive group of deserted forts and tombs in Caria that were still known in his day as "Lelegean forts"; the "Encyclopædia Britannica" 1911 identified these as ruins that could still be traced ranging from the neighborhood of Theangela and Halicarnassus as far north as Miletus, the southern limit of the "true Carians" of Pherecydes.