Hammelech is mentioned 2 times in scripture, across 1 book of the Old Testament. First named in scripture around 606 BC.
The king’s, the father of Jerahmeel, mentioned in Jer. 36:26. Some take this word as a common noun, “the king”, and understand that Jerahmeel was Jehoiakim’s son. Probably, however, it is to be taken as a proper name.