Theodulf's most important work for the king known to us was his service as a royal overseer of justice, a missus dominicus. He wrote a long poem addressed to judges in which he - possibly satirically - lists the kinds of valuable objects with which judges could be bribed. In this poem he demonstrates to the reader his appreciation for objects from Roman antiquity, though the objects he describes may have been imaginary.
During Charlemagne's reign the Byzantine controversy over Iconoclasm came to an end. Theodulf wrote the Libri Carolini ("Charlemagne's Books," called so because the text was written in the name of Charlemagne), the official response of the Frankish empire to the Byzantine document produced at the Second Council of Nicaea. In that text Theodulf attacks the practice of paying religious honor to images as idolatry. This idea did not preclude Theodulf from using images in his own buildings - his private chapel at Germigny-des-Prés, France, survives with (restored) mosaic decoration of the Ark of the Covenant and angels. Theodulf wrote a hymn still used in the Roman Catholic Church for Palm Sunday, the Sunday before Easter, Gloria, laus, et honor, "Glory, praise, and honor."
Theodulf served as abbot of Fleury (Saint-Benoit-sur-Loire) and bishop of Orleans from about 798 until 818, when, accused of involvement in the conspiracy of Bernard, King of Italy, against Louis the Pious, he was deposed from his bishopric and imprisoned for some time, then exiled to the fortress at Angers, where he died in 821.