Saints Simon and Jude (1st century) apostles
Saints Simon and Jude went together as missionaries to Persia, and were martyred there, according to St Venantius Fortunatus, a poet and bishop of Poitiers in the sixth century. This may explain why so little is known about them and also why they are usually put together.
New Testament lists
In the various New Testament lists of the twelve apostles (Mt 10:2-4; Mk 3:16-19; Lk 6:14-16; Acts 1:13), the tenth and eleventh places are occupied by Simon the Zealot (also called Simon the "Cananean," the Aramaic word meaning "Zealot") and by Judas of James, also called Thaddaeus or Lebbaeus.
Jude
Jude is often, in popular usage, known as the patron of desperate causes, the "saint of last resort", the one you ask for help when all else fails. We may wonder what this is about. It may be that since his name reminds us of Judas Iscariot, there is a tendency for anyone asking a Christian brother, now with the Lord, for intercessory prayers to try one of the other apostles first. Hence, Jude has come to be called "the saint of last resort", the one whom you ask only when desperate.
Simon
Except on these lists, Simon is not mentioned by name elsewhere in the New Testament. Some modern writers have used his surname "the Zealot" as a basis for conjectures associating him, and through him perhaps even Jesus, and his original followers, with the Zealot movement described by Josephus, a Jewish independence movement with a somewhat terrorist streak.
Some unlikely people
Jesus chose some unlikely people: a former Zealot, a former (crooked) tax collector, an impetuous fisherman, two "sons of thunder" and a man named Judas Iscariot, who was to betray him. It shows that holiness does not depend on human merit, but is entirely God's creation and gift.