Let no man deceive you by any means: for that day shall not come, except there come a falling away first, and that man of sin be revealed, the son of perdition;
2 Thessalonians 2:3
While 2 Thessalonians 1 talks about the second coming of Christ, with the sun and moon being darkened, Paul digresses and tells his recipients that the Lord would not come back, the second coming, until after the Jerusalem events had transpired.
In this, there would be a great apostasy or rebellion among the Jews, as was evident for the three and a half years of the seige from 66-70AD. Further, what many attribute to a future antichrist figure, the ‘man of lawlessness’ or the ‘son of perdition’ would have been the rebel leader, the Levite named Simon from the Gallilee area, who burned the storehouses of food the Jews had, to force them to fight the Romans, rather than living quite secure within the city walls.
This man, although records are scare, did set himself up in the temple, as the headquarters of his rebellion. Additionally, it was known that the priesthood was the thing restraining much of the madness propagated by Simon, and so Simon slew the high priest Annus.
As for his destruction, the Word is two-fold. It says.
…whom the Lord will slay with the breath of His mouth and bring to an end by the appearance of His coming
2 Thessalonians 2:8b
For traditional readings, these two parts are read together. However, that does not need to be the case, as the previous chapter just began with the Second Coming events which come some time after the 70AD destruction. What the verse says is that the Lord will slay this man and that He will bring an end to Him by the appearance of His coming. Two separate things. Whether they are separated by 2000 or more years is hardly an issue, at that point. Paul does not know the time frame involved–all he knows is the spirit, or breath of Jesus will slay this rebellious leader, and, already dead, he will be brought to an end at the Second Coming. The first is specific information, and the second is in line with all the wicked who perish, who will be brought to an end at the Second Coming and final judgment.
There are alternate readings for this text, but this straight-forward approach from the text, while perhaps not the typical arrangement, certainly fits the details of the preceeding chapter, and the knowledge possessed by Paul. How Jesus chose to slay the man by the breath or spirit of His mouth is not given, other than that there was most likely some form of prophetic utterance from the true church (Revelation 19:10), but, Beyond that, it is unclear as far as our records of history relate.