In contrast to al-Kindi, who considered the subject of metaphysics to be God, al-Farabi believed that it was concerned primarily with being qua being (that is, being in and of itself), and this is related to God only to the extent that God is a principle of absolute being. Al-Kindi's view was, however, a common misconception regarding Greek philosophy amongst Muslim intellectuals at the time, and it was for this reason that Avicenna remarked that he did not understand Aristotle's Metaphysics properly until he had read a prolegomenon written by al-Farabi.