HATTO OF MAINZ: Archbishop of Mainz; b., probably in Swabia, about the middle of the ninth century; d. May 15, 913, although the place of his death is unknown. He was educated either at Ellwangen or Fulda, and in 889 was elected abbot of Reichenau. In the following year he became abbot of Ellwangen, and two years later, while still retaining these and other benefices, he was conse crated archbishop of Mainz at the desire of King Amulf, to whom he had rendered important serv- ices. He twice accompanied Arnulf to Italy (894, 896), and on the latter occasion received from Pope Formosua the pallium, and relics of St. George for his monastery of Reichenau. When Arnulf died and his young son, Louis the Child, ascended the throne in 900, Hatto's power became still greater. Together with Adelbero, bishop of Augsburg, he acted as regent throughout the brief reign of Louis (900-911), devoting his chief energies to the welfare of the kingdom and the preservation of peace; and his influence suffered little diminution at the hands of Conrad I., whom he himself had proposed as the successor of Louis.

About the name of so prominent a statesman and ecclesiastic a mass of legend soon grew up, and many tales were current of dark deeds and plans in which he was said to have been involved. He was said to have been the chief character in the treach erous murder of Count Adalbert of Badenberg, a rebel against the king, whom the archbishop induced to surrender under promise of protection. While Hatto was accompanying Conrad to the Rhine in 912, his Thuringian and Saxon estates were attacked by Duke Henry of Saxony, thus giving rise to the tradition that Hatto, unable to gain revenge openly, strangled Henry with a chain of gold. On the other hand, he is represented in many sources as irre proachable in affairs of both Church and State. He convened the important Synod of Tribur (895), built the church of St. George at Reichenau, and beautified the cathedral at Mainz. Concerning his death there were many traditions. According to Ekkehard of St. Gall, he died of " Italian fever "; according to Thietmar, his death was sudden; and according to Widukind, he expired of chagrin at the failure of his plans against Henry of Saxony. Later traditions relate that he was killed by lightning, or snatched up by the devil and hurled into the crater of Etna. The most popular legend, however, represents him as eaten by mice in his tower at Bingen on the Rhine because of his cruelty to the poor.

(A. Hauck.)

Bibliography: A letter of his to Pope John IX. is in MPL, exxxi.; J. F. Böhmer, Regesta archiepiecoporum Moguntinenaium, i., pp. xxvii. sqq., 84 sqq., Innsbruck, 1877. Consult: F. L. Dammert, Hatto L, Programm, Freiburg, 1864-65. On the legends: S. Baring-Gould, Curious Myths of the Middle Ages, pp. 447-470. London, 1872; C. J. C. Will, in Monatsschrift für rhein-westphelische Geschichteforschung, i (1875), 205 sqq.; Hauck, KD, iii. 7, 10-11, et passim.