SOME FAMOUS UNIVERSITIES. The oldest university was in Bologna in Italy, and teachers began to explain the laws of the Romans to its students eight hundred years ago. The University of Paris was called the greatest university in the Middle Ages. Its students numbered sometimes between six and seven thousand. About the same time the English universities of Oxford and Cambridge were formed, and there, many years later, a large number of the men who settled in America were educated. THE WISDOM OF THE ARABS. Students in these universities obtained several of the writings of the Greeks through the Arabs, the followers of Mohammed, who had conquered most of Spain. Long before Europeans thought of founding universities the Arabs had flourishing schools and universities in Spain. The capital of the Mohammedan Empire was first at Bagdad on the Euphrates, where once ruled Haroun-al-Raschid, the hero of the tales of the Arabian Nights. [Illustration: VIEW OF NEW COLLEGE, OXFORD Built in the fourteenth century] WHAT EUROPEANS BORROWED FROM THE ARABS. The Arabs had learned much of geography and mathematics from the Greeks, and they also found out much for themselves. The numerals which we use are Arabic; and algebra, one of our principal studies in mathematics, was thought out by the Arabs. Their learned men were deeply interested in the books of Aristotle, an ancient Greek, who had been a teacher of Alexander the Great. They translated his books into Arabic, and Christian students in Spain translated the Arabic into Latin. The great scholars at the University of Paris believed that Aristotle reasoned better than other thinkers, and took as their model the methods of reasoning found in this Latin translation of an Arabic translation of what Aristotle had written in Greek. [Illustration: THE ALCAZAR AT SEVILLE Built by the Moors in the twelfth century. Note the elaborate decoration of the Moorish architecture.] BUILDERS IN THE MIDDLE AGES. The Greeks and the Romans had been great builders, but the men of the Middle Ages succeeded in building churches, town halls, and palaces or castles which equaled in grandeur and beauty the best that the ancient builders had made. The large churches or cathedrals seem wonderful because their builders were able to place masses of stone high in the air and to cover immense spaces with beautiful vaulted roofs. Builders nowadays imitate, but not often, if ever, equal them. Fortunately the original buildings are still standing in many English and European cities: in Canterbury, Durham, and Winchester; in Paris, Chartres, and Rheims; in Cologne, Erfurt, and Strasbourg; in Barcelona and Toledo; in Milan, Venice, and Rome. [Illustration: NOTRE DAME IN PARIS View from the rear, showing the arches and buttresses]