I have a thought on this, if it helps: After the reception of St. Matthias into the original 12 Apostles replacing Judas Iscariot, nothing further is said of him, certainly in Sacred Scripture, and even from the early Fathers practically nothing is known of him. The only thing I have ever come across is a statement somewhere that after St. James was martyred in Jerusalem St. Matthias succeeded him for tending the Jerusalem congregation for the short time remaining before Jerusalem was destroyed. What he did before that or after that remains a mystery.