Our historical sources, down to his time, are few, bald, and jejune; soon after his accession they become full, satisfactory, and numerous. The ninth century, in spite of all its troublous times, is far better known to us than the eighth. Charles kept the best of his scholars about his Court, and treated them as familiar friends. When he was settled down at Aachen for the winter, and was at rest from wars, he gathered them about him to discuss all manners of subjects, from astronomy to logic. The literary circle assumed old classical names. Alcuin called himself Flaccus, Charles was addressed as King David, other scholars styled themselves Homer, Mopsus, and Damætas. Their discussions were often fruitless, and sometimes childish, but it was something new in Western Christendom to find a whole group of scholars busied in discussions of any sort whatever. After looking back at the blank darkness of the seventh century, we find the court of Charles the Great a very centre of light and wisdom. In it lay the promise of great things in the future, a promise for which we have looked in vain in any period of the preceding ages. It was not only in literature that Charles busied his leisure hours. He was a great admirer of music, both secular and ecclesiastical. His ear was charmed by the Gregorian chants which he heard at Rome, and he took back with him Italian choirmasters to teach the churchmen of the north the sonorous cadences of the sainted Pope. [Sidenote: Charles as builder.] He was also a mighty builder. At Aachen he reared a great palace for himself and a magnificent cathedral. The former has perished, but enough survives of the latter to show the exact extent to which Romanesque architecture had developed by his time. So much was he set on making it the most magnificent basilica to the north of the Alps, that when he found his own workmen unable to carry out his ideas, he sent for ancient columns and marbles from distant Rome and Ravenna. His own coffin was a splendid Roman sarcophagus, probably procured from Italy. He constructed palaces in two other Austrasian towns besides Aachen, the old royal seats of Nimuegen and Engelheim, for he was Austrasian to the core, and always made the land of his ancestors his favourite dwelling. He built a bridge at Mainz five hundred yards long, the first effort of Frankish engineering in that class of structure. Unfortunately it was destroyed by fire in 813, and never renewed. Another piece of work which testifies to his interest in engineering was a canal to join the Rhine and Danube, by means of their tributaries, the Altmühl and the Rednitz.