Among the unceasing labors and feats of monasticism, abbot and confessor, Pr. Theodore wrote many books. The main of his creations are as follows:

A rule setting out the order of church services throughout the year.

Canons and Three Songs with Stichera Included in the Lenten Triodion.

A dogmatic sermon on the veneration of holy icons;

Epistle to the Emperor Theophilus and Letter to Pr. Plato, about the same. (Printed in the 99th volume of the Patrology of Minya).

Three Homilies, Seven Chapters, and Other Polemical Discourses Written in Refutation of the Iconoclastic Heresy. (Printed in the same place)

Homilies on the Feasts of the Lord, the Mother of God, in honor of the Forerunner and other Saints. (Some of them are printed in the same place).

Four chapters on the ascetic life;

Commentary on the ascetic rule of Basil the Great. (Ibid.).

The Five Books of Letters. (Two books containing 278 Letters were printed by Migne in his Patrology, and in Russian translation were published in St. Petersburg in 1867.

The Rite of the Studite Monastery; Rules on the confession of sins and penances. (Printed in the Patrology of Minya).

And finally, the Catechumens, or Monastic Teachings, and the Testament.

Two collections of these teachings have come down to us: the Great Collection of Teachings (ἡ Μεγάλη Κατηχητική), which consisted of 254 teachings, and the Small Collection (ἡ Μικρὰ Κατήχησις) of 135 teachings. The Hellenic Greek original of them remains unpublished to this day, with the exception of four sermons printed by Minius in Hellenic Greek. The rest of the teachings of Pr. Theodore are known only from translations: Latin (in the Patrology of Migna) and Modern Greek, published in Venice in 1770.

The ninety-five teachings and testament of Pr. Theodore the Studite was translated from Modern Greek into Slavonic by the famous elder, archimandrite of the Moldavian German Monastery, Paisius Velichkovsky [4]. These same ninety-five sermons are now published in Russian translation; under which the translators, in the absence of a Hellenic Greek original, adhered to the Modern Greek translation, which was accepted in the East, in Greek monasteries, for general use. The Modern Greek translation was carefully compared with the Slavonic translation of Elder Paisius; but we used the Latin translation cautiously, in a few cases where the modern Greek translation seemed to us obscure and not entirely satisfactory. The testament of Pr. Theodore and those teachings that Minya published in the Hellenic Greek original, (according to our edition the 13th, 57th, 69th and 95th) were translated from this original by us.