Various translations of some works and compilations of ancient medical texts are known from the 7th century. Hunayn ibn Ishaq, the leader of a team of translators at the House of Wisdom in Baghdad played a key role with regard to the translation of the entire known corpus of classical medical literature. Caliph Al-Ma'mun had sent envoys to the Byzantine emperor Theophilos, asking him to provide whatever classical texts he had available. Thus, the great medical texts of Hippocrates and Galen were translated into Arabian, as well as works of Pythagoras, Akron of Agrigent, Democritus, Polybos, Diogenes of Apollonia, medical works attributed to Plato, Aristotle, Mnesitheus of Athens, Xenocrates, Pedanius Dioscorides, Kriton, Soranus of Ephesus, Archigenes, Antyllus, Rufus of Ephesus were translated from the original texts, other works including those of Erasistratos were known by their citations in Galens works.