Anonymus 423 was the owner of a seal dateable to the seventh century: Speck, Bleisiegel 138. Obv.: eagle, with outspread wings, facing left, under a star. Rev.: cruciform monogram, partly lost, of uncertain meaning, containing the letters α, κ, χ, ο and υ, with perhaps λ and ι (if not μ or ν). Speck suggested Καλλιμάχου or perhaps Νικομάχου; another possibility may be Σχολαστικίου.

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