When was St. Matthew canonized?

Matthew was an apostle of Our Lord.

He repented of his life as a dishonest tax collector.

Matthew wrote one of the four Gospels.

He was a martyr for his faith.
St. Matthew was not canonized. He was proclaimed a saint by early

Christians because of his martyrdom. The canonization process did not

come into existence until the 12th century. In the primitive Church,

martyrs were immediately recognized as witnessing to the perfection of

Christian life on earth, having shown the ultimate proof of their love for

Christ by the offering of their lives. By the sacrifice of their lives

for Christ, they attained Heaven in eternal glory and were indissolubly

united to the Lord, the Head of the Mystical Body.