I have hard of the accusative case theory as well, but I'm afraid, this is no sufficient answer. The name
MARIA does appear in the *Greek* New Testament as well as
MARIAM: read Mt 27,55 (
Maria) and 28,1 (
Mariam), nominative case both times. (This is
Mary Magdalene;
Jesus' mother is called
MARIA only in an old Greek manuscript, not in the official text: Lk 2,19. The sister of
Lazarus is referred to as
MARIA,
MARIAN and
MARIAM.
So I do not quite see, how a Latin translation would have influenced this. To me it looks like
MARIA and
MARIAM (and
MARIAN) were used as Greek forms of the Hebrew MIRYAM. But since when?