“And he departed, and began to publish in Decapolis how great things Jesus had done for him: and all men did marvel.”
Mark 5:20 — Greek Interlinear
Church Fathers on Mark 5:20
Those who were in the ship enquired among themselves, 'What manner of man is this?' and now it is made known Who He is by the testimony of His enemies. For the demoniac came up confessing that He was the Son of God. Proceeding to which circumstance the Evangelist says, 'And they came over unto the other side, &c.'
Geraza is a noted town of Arabia, across the Jordan, near mount Galaad, which the tribe of Manasseh held, not far from the lake of Tiberias, into which the swine were precipitated.
Though Matthew says that there were two, Mark and Luke mention one, that you may understand that one of them was a more illustrious person, concerning whose state that country was much afflicted.