Simon Bar-Jona who Jesus re-named Peter was initially credited with writing the letters 1 Peter & 2 Peter and also has been acclaimed as the initial Vicar of Christ (Pope)

Peter's brother Andrew

James son of Zebedee, AKA the Greater, was initially credited with writing the letter of James,

James' brother John was initially credited with writing both the Gospel of John and the Apocalypse (Revelation) he was also entrusted with the care of Jesus' mother Mary

Philip

Bartholomew AKA Nathanael

Thomas

Matthew AKA the tax collector, was initially credited with writing the Gospel of Matthew

James son of Alphaeus, AKA the Lesser

Thaddaeus (AKA Jude/Judas, brother of James) The letter of Jude was originally attributed to Jude Thaddaeus

Simon AKA the Cananean (the Zealot)

Matthias who was chosen to replace the traitor Judas Iscariot


Holy Days of Obligation for the Catholic Church


Holy Mary Mother of God, January 1 (Theotokos - God Bearer)

Epiphany (U.S.: Sunday after January 1)

Easter Sunday (as are all Sundays)

Ascension, Thursday 40 days after Easter (that Sunday in some dioceses)

Corpus Christi, Thursday after Trinity Sunday (Sunday after Trinity in some dioceses)

Assumption, August 15

St. Joseph, March 19

Apostles Saints. Peter and Paul (not normally observed)

All Saints, November 1

Immaculate Conception, December 8

The Nativity of Our Lord Jesus Christ (Christmas), December 25