All that can be known for sure about St. Matthias is found in Acts of the Apostles, Chapter 1, verses 20 thru 26. Peter, initiating the replacement of the late Judas Iscariot, stated “Wherefore of these men who have companied with us all the time that the Lord Jesus came in and went out among us, beginning from the baptism of John, until the day wherein he was taken up from us, one of these must be made a witness with us of his resurrection.” *
Following a prayer imploring the Lord to show His choice, the lot fell to Matthias. Thus, he became the thirteenth apostle. Note that I consider him as number 13 as opposed to others who consider him the replacement for the twelfth, Judas. This is not from contrariness, but from my contention that Jesus chose the betrayer to be number 12, and sent him out with the other 11 to preach and heal, and even ate the last meal with him. If He had wanted to “unchoose” him, there was plenty of opportunity to do so, right up to the treacherous kiss in the garden.
Granted, the other apostles were motivated by the hole in their ranks, and Peter even quoted Psalm 109 “his bishopric let another take.” ** referring to the open apostolate. I don’t see that as a reason to put Matthias onto the evangelical playing field with Judas’ number pinned on his jersey. Of course, it does mess with the biblical numerology with the 12 apostles. But what about St. Paul? Isn’t he an apostle? Do we make him 12b to keep the apostolic numbers consistent?
Matthias was never mentioned in scripture either before or after his election. In many ways he is the “forgotten” apostle, usually not listed as one of the 12, and not even included with the other 11 and St. Paul in the Communicantes (“In communion with…”) section of Eucharistic Prayer 1. Matthias can be found in the Intercessions section later on, listed after John the Baptist and Stephen.
There is much speculation, some based on apocryphal sources of how Matthias lived out his apostolate. Those who are curious can search the web or consult one of the links below.
Suffice it to say the 13th Apostle finished his ministry in the same way he started. Quietly, unobtrusively, but effectively recognized as a follower of our Lord Jesus Christ.
May those who claim to be Matthiasts live as faithfully and humbly as he did.
*Acts 1:21-22 DRA (Douay-Rheims 1899 American Edition)
**Psalm 109:8b DRA
A few links for more information on St. Matthias:
https://www.catholic.org/saints/saint.php?saint_id=5