Flavius Josephus, Antiquities of the Jews
William Whiston, A.M., Ed.

[155] But king Solomon subdued to himself the remnant of the Canaanites that had not before submitted to him; those I mean that dwelt in Mount Lebanon, and as far as the city Hamath; and ordered them to pay tribute. He also chose out of them every year such as were to serve him in the meanest offices, and to do his domestic works, and to follow husbandry; for none of the Hebrews were servants [in such low employments]: nor was it reasonable, that when God had brought so many nations under their power, they should depress their own people to such mean offices of life, rather than those nations; while all the Israelites were concerned in warlike affairs, and were in armor; and were set over the chariots and the horses, rather than leading the life of slaves. He appointed also five hundred and fifty rulers over those Canaanites who were reduced to such domestic slavery, who received the entire care of them from the king, and instructed them in those labors and operations wherein he wanted their assistance.