Bacauda was the bishop of Formia located on the coast of the Tyrrhenian Sea, roughly halfway between Rome and Naples. In Letter 1.8 ([2174]), Gregory granted to Bacauda and his clergy the revenues of the church of Minturno which was completely destitute of clergy. It was done also because the bishopric of Formia was apparently very poor. It may be the reason why some junior clergy had left Formia for Sicily which was in desparate need for candidates to higher clerical ranks (see, e.g., [2179]).
It may be significant that, in Gregory's letter, Bacauda is said to have neither a presbyter (in singular), nor deacons (in plural). It seems that Bacauda considered one presbyter to be enough for the needs of his city or, possibly, that he had no means to support more than a single presbyter.