Vespasian exorcised demons.

“Demons … are none other than the spirits of the wicked …” says Josephus. (Wars, Book 7, Chapter 6, Section 3, 185). Josephus deemed those rebelling against Rome wicked, demons. When trying to understand Luke 8: 30 where a demon’s name is Legion, the interpretation is that legion is a Roman term for thousands; so, there were thousands of demons. Let us see how Josephus, in his account of history, identifies thousands of demons not as being Romans but rebels against Rome.

John [a rebel leader, recruited rebel followers and] filled the entire countryside with ten thousand instances of wickedness, such as a man who was already hardened sufficiently in his impiety towards God would naturally do; for the food was unlawful that was set upon this table, and he rejected those purifications that the law of his country had ordained; so that it was no longer a wonder if he, who was so mad in his impiety towards God, did not observe any rules of gentleness and common affection towards men.. (Wars of the Jews, Book 7, Chapter 8, Section 1, 263-264)

Vespasian exorcised these demons that possessed not a man but a city. The way this was done is as indicated in Matthew 8: 29: the demons recognized they were inferior to Jesus in power and authority.

The Exorcism:

…Vespasian marched against Gadara, the metropolis of Perea, which was a place of strength, and entered that city…
…The seditious despaired of keeping possession of the city, being inferior in number to their enemies; hence, they resolved to fly, to rush away.

[The city was exorcised of its demons by the overpowering strength and authority of Jesus Exorcist-figure, Vespasian, but not before demons viciously killed one of the men who brought Vespasian, “the exorcist,” to the city.]

Abridged Quote
Josephus. The Wars of the Jews, Book 4,
Chapter 7, Section 3, 413, 415-416