After serving as principal of the convent school, he was elected about 805 abbot of the monastery on Mt. Castellion. In around 814 he moved his monks a few miles away and founded the monastery of St Mihiel on the banks of the River Meuse, in the diocese of Verdun. Charlemagne employed him to write the letter to Pope Leo III, in which was communicated the decision of the Council of Aachen respecting the adoption of the Filioque, and sent him to Rome with the commissioners to lay the matter before the pope. He acted as secretary, and drew up the protocol. Louis the Pious showed him equal consideration, endowed his monastery, and in 824 appointed him to act with Frothar of Toul as arbitrator between Ismund, abbot of Moyenmoutier Abbey, and his monks. Smaragdus died about 840.
Works
His writings show diligence and piety. His published works in prose are:
Collections of Comments on the Epistle and Gospel for each holy day in the year,, a collection in one hundred chapters of ascetic rules and reflections concerning the principal duties and virtues of the monastic life. It is for the most part a compilation. The sources are the Collectiones patrum of Cassian and the writings of Gregory the Great. Smaragdus made it after his elevation to the abbotship and enjoined its daily evening reading upon his monks. It proved to be a very popular work, was widely circulated during the Middle Age, and was repeatedly published in the early modern period.
Commentary upon the rule of St. Benedict undertaken in aid of the monastic reforms instituted by the Council of Aachen. It is characterised by great strictness.
The Royal way dedicated to Louis the Pious while king of Aquitania. So Ebert, l.c. p. III, it consists of thirty-two chapters of moral and spiritual counsels, which if faithfully followed will conduct an earthly king into the heavenly kingdom. The work is really only an adaptation of the Diadem to the wants of the secular life.
Acts of the Roman conference Migne, CII. col. 971–976, the protocol already mentioned.
Epistle of Charles the Great to Leo the Pope upon the procession of the Holy Spirit, Migne, XCVIII. col. 923–929. the letter mentioned above.
Epistle of Frotharius and Smaragdus to the Emperor Louis, Migne, CVI. col, 865–866. the report of the arbitrators.
A larger grammar or a commentary upon Donatus. This is his earliest work, written at the request of his scholars, probably between 800 and 805. It is still unprinted, except a small portion in Mabillon, Vetera analectam, Nov. ed. pp. 357, 358.
There remain in manuscript a Commentary on the Prophets, and a History of the Monastery of St. Michael Smaragdus also wrote poetry. Besides a hymn to Christ there have been preserved his metrical introductions to his Collections and Commentary on the rule of St. Benedict, of which the first has twenty-nine lines in hexameter, and the second thirty-seven distichs.
