Why was the book of Esther included in the canon?

The book of Esther is included in both the Jewish canon and Christian canons of all denominations. However, it seems to have enjoyed a questionable status for much longer than any other of the now-accepted writings. For example, it is the only Old Testament book not to be found at Qumran, it is one of the few OT books not referenced by Sirach, it is omitted from Melito of Sardis's canon, and Athanasius also expressly categorized it with the Apocrypha as useful but not canonical. Jerome, whose opinion is often cited by Protestants in discussions of the canon, counted Esther as canonical but not the deuterocanonical books (although it seems he changed his opinion on the deuterocanonical books at some point in his career). I haven't read Jerome's comments myself but, usually his reason is explained to be that the canonical books were the ones where the Hebrew manuscripts still existed while the others were only preserved in Greek (or were composed in Greek). However, Jerome seems to have known of Hebrew manuscripts of 1st Maccabees, so there must be something else going on to distinguish it from Esther. Protestants usually cite as the main criterion for OT canonicity some prophetic authority guaranteeing the divine inspiration of a book. However, Esther has no association with the prophets, unlike any other book of the Protestant OT canon. However, Esther was included in the canon by the Council of Rome (382) and by all subsequent streams of Christian thought. Why? What reasoning lead the Church to set aside the doubts specifically about the book of Esther that apparently had existed for quite a while prior? **This is a historical question.** I am not asking why it is included in the canon by Protestants or Catholics today, but rather why it was included starting in the 4th century, i.e. why the doubt which originally surrounded the book was cleared up.