Three of the four Gospel writers list the twelve called by Jesus to be apostles. (John has no list.) Six of them had the same names as three of Christ's half-brothers, (two of each): Simon, James, and Judas, (Matthew 13:55). There were thus two disciples named Judas, only one of whom actually became an apostle after the Resurrection. (Judas Iscariot betrayed Jesus and committed suicide.)
Only Luke, the Greek physician who traveled with the Apostle Paul and wrote both a Gospel and the Acts of the Apostles, even mentions that this man was named Judas. Matthew and Mark both call him Lebbaeus or Thaddeus. (Matthew says that his surname was Thaddeus). In the start of his Epistle, he calls himself, "Jude the servant of Jesus Christ and brother of James." If it were not for Luke, we would not know about his name being "Judas" at all.
I found it interesting, this difference in how he was named. Matthew and Mark, the two Jewish authors, referred to him by what may be his Roman name, while the Greek physician, Luke, is the one to point out his Hebraic name. None of them states why. Any guess at their reasons is just that: a guess. (Not even Matthew Henry appears to have made one.)
At first, I believed that the other Apostles were using the fact that he had a Roman name to be kind and avoid for his sake the intense stigma attached to the name "Judas," especially in the early Church. Maybe this is true. There is a more practical explanation as well: while the Lord gave a new name, (or "surname"), to Peter, which from then on distinguished him from the other Simon, ("the Canaanite" or "the Zealot"), Jesus did not do this for James' brother Judas. In everyday life, while following Jesus around Judea and Galilee, the twelve disciples may simply have used this man's Roman name so that he knew when they were calling out to him and not to Iscariot. (While I think that we tend to assume that Judas Iscariot was unpopular, which would be based on hindsight, he was given custody of their money, so they must have called out his name fairly often whenever they wanted any.)
This second explanation seems more consistent with who used his Roman name, versus who used his Jewish name. I was at first a bit puzzled by why it was Luke, who was not a Jew, that made us aware he was named Judas, compared with the two who were Jewish and traveled around with him longer. I realized that if it was an established habit for Matthew and Mark to call him "Lebbaeus" or "Thaddeus," because of their practical need during Jesus' ministry to distinguish the two Judases, but not for Luke, who recorded events afterwards, this would help to explain it.
The apostle Jude is not the only person of whom we see little mention in Scripture. Except for his writing of an epistle, the lists of names in these three Gospels are our only references to him. What little we know of him is what Scripture tells us of the Apostles in general: he traveled with Jesus, was sent out by twos to preach during Christ's ministry, (possibly with his brother James, but that is another assumption), fled with the others at Christ's arrest, was with them in the Upper Room at Jesus' reappearance and at Pentecost, and evidently served faithfully afterward. We are not told why he apparently had a Roman name when none is given for any other apostle. We know from the life of Paul that some Jewish men were born with Roman citizenship, but not all.
This can happen to us as well. We may seem to have promise or privilege when we are younger; we may serve Christ faithfully for a long time; we may have no confusion about our calling and no great failures in following it. Yet we may get glossed over and seemingly ignored while acclaim and fame seem to be showered on others. The acclaim of people is sometimes not accurately given; it is the reward of Christ that will matter.
(See "About Me")