NET
21 On a day determined in advance, Herod put on his royal robes, sat down on the judgment seat, and made a speech to them.
Darby
21 And on a set day, clothed in royal apparel and sitting on the elevated seat [of honour], Herod made a public oration to them.
KJV
21 And upon a set day Herod, arrayed in royal apparel, sat upon his throne, and made an oration unto them.