they had been enemies: There was a history of conflict between Herod Antipas and Pilate. Herod and three of his brothers had earlier accused Pilate before Tiberius Caesar. This happened when Pilate placed gold shields with pagan symbols in Jerusalem, and Tiberius ordered him to remove them.
Pilate also ruled Judea, a region that Herod Antipas’s father, Herod the Great, had once ruled. Antipas hoped that he might one day rule this area himself.