Plus Jesus said explicitly, if someone says the Messiah has come, do not believe them (Matt. 24:23-28). The full preterist position, IMV, is actually heresy.
Jesus was right, of course.
In Revelation 20, we see that a false prophet is defeated and thrown into the abyss. Jesus warns of these false messiahs and prophets (
Mt 24:5, 11, 24). These charlatans whom John also refers to as false teachers (
Rv 2:14-15; 19:20) were not in short supply. Josephus reports that the Jewish Zealots suborned many false prophets to rally the people against Rome (
Wars 6.5.2). The few decades following the crucifixion are often referred to as the Messianic Age, and with good reason. Many people claimed to be the messiah.
One individual who seduced a large following was Theudas, a self-proclaimed prophet whom Josephus calls a magician. This man deluded several hundred souls into following him to the Jordan River, which he promised to divide in order to provide passage through as they retreated from Rome. It did not work; Fadus, the Procurator of Judea, sent troops after him and his band, and captured and slew them. Theudas ended up beheaded (
Antiquities 20.5.1).
Another false messiah who arose shortly after Christ was Judas the Galilean, who led a failed messianic movement to protest tribute to Rome, both in taxation and in allegiance to its emperor. Josephus doesn’t relate the death of Judas but does record the execution of his two sons (
Antiquities 20.5.2), and calls him a teacher of his own peculiar sect (
Wars 2.8.1), referring to the Zealots.
Doubts persist as to whether this Theudas and Judas of whom Josephus writes are the same as the two characters of whom Luke writes in the Book of Acts (5:36-37), but in either case, these false teachers came to nothing. In the end, their lives mattered not a whit to the world at large.
Luke records the fate of another false prophet, Bar-Jesus, after he opposes the Gospel that Paul and Barnabas preach (
Acts 13:6-12). His life also came to nothing.
The last false messiah of note during the Jewish Wars was Simon bar Kokhba. Simon bar Kokhba led his insurgents in a revolt against Roman occupation in Judea after the Great Revolt and Kito’s War ended in failure for the Jews. History estimates that over half a million Jews were killed in this third and final campaign of the Jewish Wars, directly at the hands of the Romans and also due to famine and disease. The Bar Kokhba Revolt was the definitive and final message from God that His judgment had come, that the Temple Age had ended.
It’s over; give it a rest already. Bar Kokhba died in the fortress of Betar, and like the false messiahs before him, was laid to rest without effecting the change he intended. Rome maintained its presence. The declining Jewish state came once and for all to a complete collapse and Judean identity utterly vanished.
The pseudo-christs who rose up to liberate Israel and Judea from their pagan overlords wooed followers with their boastful language and military prowess. They envisioned themselves claiming victories and returning home as heroes. They saw themselves ensconced in history as mighty warriors and faithful servants who would restore the glory of their homeland. They all failed.
Imposters were not unique to Judaism. In the fledgling church, they claimed not so much to be messiahs as teachers, and by that title led many astray, as we see in 2 Timothy 3:1-4.
In his short missive, Jude also alludes to the alarming number of boasters plaguing the church. He reminds his readers that Christ’s apostles warned that these scoffers would rise in the last days, and so he warns his contemporaries to excise them from the body, as they are the ones causing the division within it (17-19). This confirms the observations of other New Testament authors. John, for example, says in no uncertain terms that false teachers had already cropped up in the world (
1 Jn 4:1, 3).