11. Therefore they did set over them taskmasters--Having first obliged them, it is thought, to pay a ruinous rent and involved them in difficulties, that new government, in pursuance of its oppressive policy, degraded them to the condition of serfs--employing them exactly as the laboring people are in the present day (driven in companies or bands), in rearing the public works, with taskmasters, who anciently had sticks--now whips--to punish the indolent, or spur on the too languid. All public or royal buildings, in ancient Egypt, were built by captives; and on some of them was placed an inscription that no free citizen had been engaged in this servile employment.
      they built for Pharaoh treasure cities--These two store-places were in the land of Goshen; and being situated near a border liable to invasion, they were fortified cities (compare 2Ch 11:1-12:16). Pithom (Greek, Patumos), lay on the eastern Pelusiac branch of the Nile, about twelve Roman miles from Heliopolis; and Raamses, called by the Septuagint Heroopolis, lay between the same branch of the Nile and the Bitter Lakes. These two fortified cities were situated, therefore, in the same valley; and the fortifications, which Pharaoh commanded to be built around both, had probably the same common object, of obstructing the entrance into Egypt, which this valley furnished the enemy from Asia [HENGSTENBERG].

JFB.