Matthias was an ethnic Jew living in Jerusalem. Matthias came from a wealthy, aristocratic family and through his father he descended from the priestly order of the Jehoiarib, which was the first of the twenty four-orders of Priests in the Temple in Jerusalem. He was the first-born son of Matthias and his wife, an unnamed Jewish noblewoman. He was the full blooded and the older brother of the Roman-Jewish HistorianJosephus. The mother of Matthias was an aristocratic woman who descended royalty and of the former ruling Hasmonean Dynasty. His paternal grandparents were Josephus and his wife, an unnamed Jewish noblewoman. The paternal grandparents of Matthias were distant relatives as they were both direct descendants of Simon Psellus. Through his father, Matthias was a descendant of the High Priest Jonathon. Jonathon may have been Alexander Jannaeus, the High Priest and Hasmonean ruler who governed Judea from 103 BC-76 BC. He was born and raised in Jerusalem. Matthias was educated alongside Josephus. Matthias; his parents and Josephus’ first wife were alive during the First Jewish–Roman War. The war occurred from 66 until 73. In the year 70 during the Roman Siege of Jerusalem; Matthias, his parents and his sister-in-law, were in the city during the siege. Matthias’ parents and sister-in-law were held as prisoners by the Jewish rebels because they didn’t trust them. Josephus who was commander-in-chief in Galilee received news through their father about the situation in Jerusalem. Josephus was unable to save their parents and his first wife as the three perished during the siege. After the capture of Jerusalem, Matthias survived the siege and became a Roman Prisoner of War. Through Josephus’ intervention, Matthias was released from Roman imprisonment. After his prison release, little is known on Matthias. There is a possibility that he may have accompanied Josephus to go and live in Rome. He was the paternal uncle of Flavius Hyrcanus, Flavius Justus and Flavius Simonides Agrippa.
