Theophylact of Ohrid
Catena Aurea · Lukasevangelium 9
Now Herod the tetrarch heard of all that was done by him: and he was perplexed, because that it was said of some, that John was risen from the dead; And of some, that Elias had appeared; and of others, that one of the old prophets was risen again. And Herod said, John have I beheaded: but who is this, of whom I hear such things? And he desired to see him.
Herod was the son of Herod the Great who slew the children, who was king, but this Herod was tetrarch. He inquired about Christ, who He was. Hence it follows, And he was perplexed.