The problem with these complex
monograms is that many times multiple solutions are possible. So if we would accept 'ΜΗΤΡΟΠΟΛΙΤΟV' then the letter A remains for the personal name. So all names containing A and any letter of 'metropolitou' would be possible. Either Paulos (ΠAVΛOV) or
Elias (HΛIA) would be much more probable than Martialos, an originally Latin name that must be very
rare if at all attested for the
Byzantine world.
Regards
Gert