Amadeus, a name very common in the ruling family of Savoy, and first borne by the eldest son of Count Humbert, in the beginning of the 11th century. The most noteworthy rulers of this name are: I. Amadeus V., count of Savoy, the son of Thomas II., born in 1249, succeeded his uncle Philip in 1285, and died at Avignon in 1323. He obtained the surname of Great. He largely increased his dominions by marriage, purchase, and donations. Among his exploits is mentioned a repulse of the Turks from Rhodes, then in the possession of the knights of St. John, a triumph which was believed to have led to the adoption of the "cross of Savoy," and the device F. E. R. T., or F E R T, generally explained by Fortitiulo ejus Rhodum tenuit; but both the exploit and the explanation are now considered unauthentic. His daughter was married to Andronicus III., emperor of Constantinople. In order to induce Pope John XXII. to preach a crusade in favor of his son-in-law, he undertook a journey to Avignon, where ho died.

II. Amadens VIII., count of Savoy, and for some time pope or anti-pope, succeeded his father Amadens VII. in 1391. He purchased the country of Gene-vois for 45,000 florins, and thus the house of Savoy became so powerful that the emperor Sigismund in 1416 erected Savoy into a duchy. John Palaeologus, duke of Montferrat, agreed to hold the marquisate of Montferrat as a fief of the house of Savoy. By marriage and donation Amadous made yet further acquisitions. In 1434, however, he abandoned his duchy to his son and retired to the monastery of Ripaille, where he lived so luxuriously that faire Ripaille became a saying in the French language, signifying to make good cheer. He had never received holy orders, but was elected pope and crowned at Basel by the cardinal of Aries, under the title of Felix V. The papal dignity was contested by Eugenius IV., who was supported by France, England, Italy, Spain, and Hungary. Eugenius died, and the cardinals at Rome elected Thomas de Sarzana (Nicholas V.). Amadous resigned the papal crown in his favor in 1449, stipulating, however, that he should be perpetual apostolical legate in his late temporal dominions, that he should continue to wear the pontifical dress except in a few particulars, that he need not go to Rome to attend any general council, and that the pope should rise to receive him, and permit him to kiss his check instead of his foot.