And they fetched up, and brought forth out of Egypt a chariot for six hundred shekels of silver, and an horse for an hundred and fifty: and so brought they out horses for all the kings of the Hittites, and for the kings of Syria, by their means. (2 Chronicles 1:17)
At the time of Solomon the Hittite empire had broken in pieces, but many minor Hittite kingdoms were still in existence in northern Syria, in the vicinity of the Euphrates.