Einhard. The Life of the Emperor Charles. Chapter 23.
He used to wear the national, that is to say, the Frank, dress ‹ next his skin a linen shirt and linen breeches, and above these a tunic fringed with silk; while hose fastened by bands covered his lower limbs, and shoes his feet, and he protected his shoulders and chest in winter by a close-fitting coat of otter or marten skins. Over all he flung a blue cloak, and he always had a sword girt about him, usually one with a gold or silver hilt and belt; he sometimes carried a jeweled sword, but only on great feastdays or at the reception of ambassadors from foreign nations. He despised foreign costumes, however handsome, and never allowed himself to be robed in them, except twice in Rome, when he donned the Roman tunic, chlamys, and shoes; the first time at the request of Pape Hadrian, the second to gratify Leo, Hadrian's successor. On great feastdays he made use of embroidered clothes and shoes bedecked with precious stones, his cloak was fastened by a golden buckle, and he appeared crowned with a diadem of gold and gems, but on other days his dress varied little from the common dress of the people.
Text source: The Life of Charlemagne by Einhard. Translated by Samuel Epes Turner.