Summary: Born into a Swabian German family and educated at the monastery of Reichenau, Hatto became the abbot of Ellwangen Abbey in 888. He met and befriended Arnulf of Carinthia, the Carolingian king of Germany and was appointed archbishop of Mainz in 891. He was on such good terms with the king that he was known throughout his life as "the heart of the king". He was president of the synod of Tribur in 895 and joined the king on his journeys to Italy in 894 and 895. When in Rome, he was praised by Pope Formosus. His position allowed him to become regent for Arnulf's young son, Louis the Child, in 899. In this role, he forced Zwentibold, an illegitimate son of Arnulf and the duke of Lorraine, to recognize his nephew as German king.
As archbishop, Hatto I was very active in his realm. He attached to his archbishopric Ellwangen and Lorsch abbeys, both early Carolingian pilgrimage sites. He sided with the Conradines in their feud with the Babenbergs over leadership in Franconia, the central-western side of Germany. In 906, he even captured and executed Adalbert, count of Babenberg, despite promises of safe conduct. Hatto remained the regent for Louis throughout his reign and when the young king died in 911, Hatto arranged for Conrad, duke of Franconia, to take the vacant throne. Hatto remained loyal to Conrad I during fighting in Saxony because Hatto did not want to lose power or influence in Thuringia, where Mainz retained many possessions. When Henry the Fowler discovered a plot for his murder being orchestrated by Hatto, he ravaged archiepiscopal lands in Saxony and Thuringia. By the end of his life, Hatto had lost much of the respect he had earned in his earlier days. He died in 913, some say due to a bolt of lightening. His name was ill remembered by the Saxons who felt his wrath during the war with Henry.
Died: 15 May 913
Other Monarch Deaths:
Valentinian II, emperor of Rome (392)
Go-Ichijo, emperor of Japan (1036)
Nur ad-Din Zangi, emir of Damascus (1174)
Ninwa Nagahide, daimyo of Japan (1585)