802
Latin
On the Holy Trinity
Alcuin of York · c. 735–804
A summary of Augustine's trinitarian teaching in three short books, followed by twenty-eight questions and answers for classroom use.
Western · Theology
801–900
The Ninth Century
56 works
c. 810–820
Latin
The Crown of Monks
Diadema Monachorum
Smaragdus of Saint-Mihiel · d. c. 840
A hundred short chapters on the virtues, arranged for reading aloud one each evening before the monks retire.
Western Monastic · Anthology
c. 810–814
Latin
In Praise of the Holy Cross
De Laudibus Sanctae Crucis
Rabanus Maurus · c. 780–856
Twenty-eight figure poems in which letters picked out within a grid of text form crosses, figures, and shapes that can be read as separate verses.
Western · Poetry
c. 810–814
Greek
The Chronicle
Chronographia
Theophanes the Confessor · c. 758–818
A year-by-year chronicle from 284 to 813, drawing on sources now lost and covering the Arab conquests and the first iconoclasm at length.
Byzantine · Chronicle
c. 815–820
Greek
Refutations of the Iconoclasts
Theodore the Studite · 759–826
Three refutations arguing that an image is a likeness and not a sharing of essence, so a portrait of Christ affirms exactly the individual humanity he assumed.
Byzantine · Polemic
c. 818–820
Greek
Refutation and Overthrow of the Iconoclast Definition
Nicephorus of Constantinople · c. 758–828
A line-by-line demolition of the iconoclast council of 815, dense with Aristotelian argument about relation, likeness, and circumscription.
Byzantine · Polemic
819
Latin
On the Education of the Clergy
De Institutione Clericorum
Rabanus Maurus · c. 780–856
What a priest must know: the orders of ministry, the sacraments, the liturgical year, and then a full defence of studying grammar, rhetoric, and the pagan classics.
Western · Education
c. 796–826
Greek
The Letters
Theodore the Studite · 759–826
Over five hundred letters written largely from exile, organising resistance to imperial religious policy and holding a scattered monastic community together by post.
Byzantine · Letters
c. 816–821
Latin
The Concord of Rules
Concordia Regularum
Benedict of Aniane · c. 747–821
Benedict's rule set clause by clause beside every other monastic rule the compiler could find, to show that it summed them all up.
Western Monastic · Rule
c. 823
Latin
On the Liturgy
Liber Officialis
Amalarius of Metz · c. 775–850
An allegorical reading of the mass in which each gesture and vestment re-enacts a moment of the passion — the deacon's movements, the folding of the cloth, the silence of the canon.
Western · Liturgy
c. 825; survives in refutation
Latin
The Apology Against Theutmir
Claudius of Turin · d. c. 827
A bishop defends stripping the images and crosses from the churches of his diocese, arguing that venerating a cross means honouring the instrument of an execution.
Western · Polemic
c. 823–828
Latin
The Letters on the Jews
Agobard of Lyon · c. 779–840
Complaints to the imperial court that Jews in Lyon enjoy protections and market privileges Christians do not, and that Christian slaves are being sold to them.
Western · Letters
c. 828
Latin
On the Instruction of the Laity
De Institutione Laicali
Jonas of Orléans · c. 780–843
A guide for married laypeople on marriage, work, almsgiving, and the duties of a household, written for a count and his wife.
Western · Ethics
9th century; date disputed
Arabic
The Apology of al-Kindi
Anonymous
A pair of letters, one inviting a Christian to Islam and the other declining at length, criticising the Qur'an's composition and Muhammad's career directly.
Church of the East · Apology
c. 828–836
Latin
The Life of Charlemagne
Vita Karoli Magni
Einhard · c. 775–840
A short life on the model of Suetonius by a courtier who knew him — his campaigns, his family, his swimming, his failure to learn to write, his dislike of foreign clothes.
Western · Biography
c. 825–840
Old Saxon
The Heliand
Anonymous
The gospel retold in alliterative Germanic verse for recently conquered Saxons: Christ as a liege-lord, the disciples as his warrior band, the nativity in a hall.
c. 831, revised 844
Latin
On the Body and Blood of the Lord
Paschasius Radbertus · c. 785–c. 865
An argument that the bread and wine become the very flesh born of Mary and hung on the cross, no less real for being invisible to the senses.
Western · Sacramental theology
c. 836
Latin
The Life of Leoba
Rudolf of Fulda · d. 865
The English abbess whom Boniface summoned to Germany, learned in scripture and canon law, consulted by bishops, and buried beside him at his own request.
Western · Biography
c. 840
Syriac
The Book of Governors
Thomas of Marga · 9th century
A history of the great monastery of Beth Abhe and its abbots, full of anecdote about monks, demons, mission journeys, and quarrels over books.
Church of the East · History
c. 830–850
Arabic
The Book of Proof
Ammar al-Basri · 9th century
A defence of Christian doctrine framed as a test for distinguishing a true religion from a false one, arguing that Christianity spread without the sword, money, or tribal advantage.
Church of the East · Apology
c. 840
Latin
The Little Garden
Hortulus
Walafrid Strabo · c. 808–849
A poem on twenty-three plants in a monastery garden — sage, rue, melon, lily, rose — with their uses in medicine and their meanings.
Western · Poetry
c. 840–842
Latin
On Liturgical Origins
Libellus de Exordiis
Walafrid Strabo · c. 808–849
A historical rather than allegorical account of where churches, altars, bells, images, vestments, and the vernacular in worship actually came from.
Western · Liturgy
843, expanded later
Greek
The Synodikon of Orthodoxy
The Synod of Constantinople
A proclamation read aloud on the first Sunday of Lent, blessing the defenders of icons by name and anathematising their opponents, expanded over the centuries as new errors were added.
Byzantine · Proclamation
c. 830–860
Greek
841–843
Latin
The Histories
Nithard · c. 800–845
A grandson of Charlemagne records the civil war among his grandsons, and quotes the Strasbourg oaths verbatim in both the Romance and Germanic vernaculars.
Western · History
841–843
Latin
Handbook for William
Liber Manualis
Dhuoda · c. 803–c. 843
A noblewoman writes to a son held as a hostage at court, on God, on loyalty, on choosing counsellors, and on praying for a family she may not see again.
Western · Handbook
c. 845
Greek
The Bibliotheca
Myriobiblos
Photius of Constantinople · c. 815–c. 893
Notes on two hundred and eighty books read by the author, each summarised and judged, many of them now lost entirely.
Byzantine · Reference
c. 848–850
Latin
The Writings on Predestination
Gottschalk of Orbais · c. 808–c. 867
Confessions and treatises arguing a double predestination — of the elect to life and the reprobate to death — from Augustine, by a monk who refused to retract.
Western · TheologyRomans
c. 847–852
Latin
The False Decretals
Decretales Pseudo-Isidorianae
Pseudo-Isidore
A vast collection of genuine canons interleaved with forged papal letters of the earliest centuries, designed to protect bishops from metropolitans and lay rulers.
Western · Canon law
c. 850
Syriac
The Biblical Commentaries
Ishodad of Merv · 9th century
Commentaries on the whole Bible in the Antiochene manner, preserving the readings of Theodore of Mopsuestia and other authors whose Greek texts were destroyed.
Church of the East · Commentary
c. 843–850
Latin
On the Body and Blood of the Lord
Ratramnus of Corbie · d. c. 868
Written at the emperor's request against his own abbot's position, arguing that the eucharist is Christ's body in figure and mystery rather than in the manner of ordinary flesh.
Western · Sacramental theology
851
Latin
On Divine Predestination
John Scotus Eriugena · c. 815–c. 877
Commissioned to refute Gottschalk, he argues that since God is simple and outside time there can be no double anything in him, and that evil has no substance to be predestined.
Western · Theology
854
Latin
The Luminous Indiculus
Paulus Albarus · c. 800–861
A defence of the Córdoba martyrs that breaks off to lament that young Christians now read Arabic poetry with delight and can barely write a decent Latin letter.
Western · Polemic
c. 855
Latin
On Christian Rulers
De Rectoribus Christianis
Sedulius Scottus · 9th century
Advice to a king in alternating prose and verse: choose counsellors well, tax lightly, protect churches, and remember that a ruler's private vices become public disasters.
Celtic · Political theory
c. 851–856
Latin
Memorial of the Saints
Memoriale Sanctorum
Eulogius of Córdoba · c. 800–859
An account of the Christians of Córdoba who sought execution by denouncing Muhammad publicly, defended by the author against fellow Christians who thought them suicides.
Western · Martyrology
c. 856–870
Syriac
The Apologetic Treatise
Nonnus of Nisibis · 9th century
A defence of Christian doctrine written in Armenia against both Muslim objections and rival Christian christologies, by a scholar imprisoned in Baghdad.
Miaphysite · Apology
c. 850–900
Old English
The Old English Martyrology
Anonymous
Short prose entries for saints through the year, each giving the day, the manner of death, and often a concrete detail found in no other source.
Anglo-Saxon · Martyrology
860
Latin
On the Divorce of Lothar and Theutberga
Hincmar of Reims · c. 806–882
A long legal opinion on a king's attempt to divorce his queen, covering consent, consummation, sorcery, and the validity of trial by ordeal.
Western · Canon law
c. 860–862
Latin
The Latin Dionysius
John Scotus Eriugena · c. 815–c. 877
A Latin version of the whole Dionysian corpus, made from a Greek manuscript the Byzantine emperor had sent as a diplomatic gift.
Western · Translation
c. 862–867
Latin
On the Division of Nature
Periphyseon
John Scotus Eriugena · c. 815–c. 877
A dialogue dividing all reality into four kinds of nature and following creation out from God and back into him, drawing on Greek fathers almost nobody in the West could read.
Western · Philosophy