He became a member of the Hofkapelle, and as a court chaplain was closely connected with Abbot Grimald, in whose monastery he lived temporarily.
In the early 840's, at the request of Gundram, court chaplain to Louis the Pious and nephew of Rabanus Maurus, Ermenrich wrote the Vita Suaolonis of Saint Solus of Solnhofen, an Anglo-Saxon missionary of Fulda.
In an extensive letter to Grimald, which was intended for a wider circle of readers, he also showed Greek knowledge and conceived a planned but not preserved metric Vita S. Galli.
[6] In his time, great efforts were made to integrate newly Christianized areas in the eastern part of the church organization of the Diocese of Passau.
[8] However, the missionary work of Methodius and his brother had great success among Slavs in part because they used the people's native language rather than Latin or Greek.
Unbeknownst to Rome, Methodius was imprisoned in 870 in an abbey in Germany by King Louis the German and the East Frankish bishops: Adalwin of Salzburg, Ermanrich of Passau, and Anno of Freising who objected to his use of the Old Church Slavonic in the liturgy and his encroachment on their jurisdiction in Moravia.