Adam Clarke on Matthew 14:6

Herod's birth-day - Either the day in which he was born, or the day on which he began to reign; for both were termed birth-days. See 1Sam 13:1, and Hos 7:5. The kings of Persia were accustomed to reject no petition that was preferred to them during the entertainment. See Herodotus in Calliope, and Est 5:3.

The daughter - danced - This was Salome, mentioned before. Danced: by a literal rendering of the saltavit of the Vulgate, in my old MS. of the English Bible, the whole of this business seems to be treated with sovereign contempt: for thus says the translator, Shee leped in the myddle.