In the history of Western philosophy the role played by texts written in Arabic is crucial. This can be seen from the sheer volume of works that were translated (see the table that follows this chapter). We have hints of Arabic-speaking teachers of philosophy. Adelard of Bath (fl. 1116-50) speaks of his studia Arabica/Arabum studia (in reference to natural philosophy) and magistri, which he probably encountered in southern Italy and Sicily. Stephen of Pisa (fl. 1127), who wrote on cosmology in Antioch, expresses his debt to “a certain Arab.” Kamal al-Din ibn Yunus of Mosul (d. 1242), the greatest Muslim teacher of his time, in turn, boasted of Christians among his pupils; one of Ibn Yunus' pupils, Siraj al-Din Urmawi, became a member of Frederick II Hohenstaufen’s household and wrote a book on logic for him. Andrea Alpago (d. before 1546) acquired knowledge of Avicenna’s psychology from the Shī'ite scholar Muhammad ibn Makkī Shams al-Dīn al-Dimashqī (d. 1531) in Damascus. But it is through the surviving Arabic texts and their translations that we can best gauge the extent of the impact of Arabic philosophy. The works translated reflect the various genres current in Arabic.