during the same period authored several major works of medicine codifying and advancing the knowledge of this field. In the second century CE the Greek trained physician Galen went to Rome where he wrote numerous works that dominated European medicine through the Renaissance. Hellenized writers in Egypt also produced compendia of knowledge using the resources of the great library at Alexandria, such as Euclid whose Elements of geometry remains a standard reference to today. Ptolemy's work on astronomy dominated through the Middle Ages. Scholars in Rome continued the practice of writing compendia of knowledge, including Varro, Pliny the Elder, and Strabo. While much of Roman accomplishment was in material culture of construction, Vitruvius documented much of the contemporary practice to influence design until today. Agriculture also became an important area for manuals, such as Palladius' compendium. Numerous manuals of rhetoric and rhetorical education that were to influence future generations also appeared, such as the anonymous Rhetorica ad Herennium, Cicero's de Oratore and Quintilian's Institutio Oratoria. Islamic learning With the fall of Rome, the Middle East became the crossroads for learning, with knowledge bearing texts from the West and East meeting in Byzantium, Damascus, and then Baghdad. In Baghdad a research institute (or House of Wisdom) with a large library was founded, where Greek works of medicine, philosophy, mathematics and astronomy were translated into Arabic, along with Indian works on mathematics and therapeutics. To these texts, philosophers such as Al-Kindi and Avicenna and astronomers such as Al-Farqhani made new contributions. Al-Kharazami authored the first work on algebra, drawing on both Greek and Indian resources. The centrality of the Quran to the new Islamic religion also led to growth of Arabic Linguistics. From Baghdad knowledge and texts were to flow back to South Asia and down through Africa, with a large collection of books and an educational center around the Sankhore Mosque in Timbuktu, the seat of the Songhai Empire. During this period the deposed Abbasid Caliphate moved its seat of power and learning to Córdoba, now in Spain, where they founded a major library which reintroduced many of the classic texts back into Europe along with texts of Arab learning. Early universities in Europe The reintroduction of classic texts into Europe through the library and intercultural intellectual culture in Córdoba, including works of Plato, Aristotle, Euclid, Ptolemy and Galen, along with Arabic texts such as by Avicenna and Al-Kharazami created a