Metaphysics, first philosophy, or divine science has always been a subject of controversy. Too often medieval Arabic metaphysics is regarded as either simply a paraphrase of or a commentary on Aristotle’s Metaphysics, or a curious and rather unsuccessful blend of Aristotelian metaphysics and Neoplatonism. Cristina D'Ancona has shown the superficiality of this latter approach by highlighting how carefully and creatively the “falāsifa” or Hellenizing philosophers used the various Greek sources, such as the works of Aristotle, the Plotiniana Arabica (a group of texts based on Plotinus and including the so-called Aristotle’s Theology derived from Enneads IV-VI), and the Liber de Causis, adapted from Proclus' Theology and known in Arabic as The Book of the Pure Good. Yet Greek sources are not enough to explain some developments. In 1979 Richard Frank argued that falsafa (the Arabic transliteration of the Greek term for philosophy, highlighting its foreign origin) is not immune to the influence of kalāmor Islamic theology, which had elaborated an ontology of its own. More recently, though controversially, he has argued that even al-Ghazālī, the famous author of the Incoherence of the Philosophers and the staunch protector of orthodox Sunni Islam, is himself deeply influenced by Avicenna.