Legend seems to read
ΦΛA
VEIA
NOC
Greek 'Phlaueianos', which must be a transliteration of Flavianus. This is a weird little seal. The form and
fabric looks to be
Byzantine, but not much else does. The name is Latin, and it is in the nominative case when seal legends in late-antiquity virtually always use a
genitive ('Phlaueianou'). Also, the
obv. iconography is not something I have seen before. Normally, two
portraits facing each other like these would depict a married couple, of which there are tons of examples known in late-Roman times, but both busts seem to be male. They seem to be two citizens, as they lack the
laurel wreath or
nimbus that would make them emperor or saint. The seal does seem ancient to me, as far as I can tell from the photo, and I would tentatively date it to the 5th to early 6th century.
Regards
Gert