Below, I have listed the principal authorities in different disciplines used or written during the long Middle Ages from 1000 to 1600. It is important to note that not all of these works were used or available at the same times. For instance, Thomas's Summa theologiae was only written in the second half of the thirteenth century and only embraced as a standard textbook in the sixteenth century. Suarez's Disputationes Metaphysicae was only written at the end of the sixteenth century.

I. Sciences

A. Speculative Sciences

1. Divine Science / Theology

i. Sacred Theology: 

Principal authority: Sacred Scripture (i.e., the Bible)

Principal patristic authorities: Pseudo-Dionysius (Corpus Dionysiacum: Divine Names, Mystical Theology, Celstial Hierarchy, Ecclesiastical Hierarchy), Boethius (De Trinitate, Contra Eutychen et Nestorium, Quomodo substantiae [De hebdomadibus], Consolatio philosophiae), Augustine (De Trinitate), Hilary of Poitiers (De Trinitate)

Principal scholastic textbooks: Peter Lombard (Sentences), Thomas Aquinas, OP (Summa theologiae, Catena aurea in quatuor Evangelia)

ii. Metaphysics [i.e., First Philosophy; Natural Theology; Ontology; Wisdom]: Aristotle (Metaphysics), Anonymous (Liber de causis), Avicenna (Metaphysics of the Healing), Plato (Timaeus), Francisco Suarez, SJ (Disputationes Metaphysicae)

2. Mathematics (see Quadrivium)

3. Natural philosophy [i.e., Natural science]

i. Physics: Aristotle (Physics); Plato (Timaeus)

ii. Chemistry: Aristotle (De generatione et corruptione); Plato (Timaeus)

iii. Psychology: Aristotle (De anima, De sensu et sensato, De memoria et reminiscentia, De somno et vigilia), Avicenna (Liber de anima); Plato (Timaeus)

iv. Biology: Aristotle (De partibus animalium, De historia animalium, De progressu animalium, De motu animalium, De iuventute, De respiratione, De morte, De longitudine et brevitate vitae), Galen (Galenic corpus [misc.]); Plato (Timaeus)

v. Cosmology: Aristotle (De caelo et mundo [NB: This work studies the physical causes of the motion of astronomical bodies]), Ptolemy (Almagest [NB: This work studies astronomical bodies using principles borrowed from mathematical disciplines]); Plato (Timaeus)

B. Morals / Practical Sciences

1. Individual ethics: Aristotle (Nicomachean Ethics, Ethica Eudemia, Magna moralia), Cicero (De officiis, Tusculanae Disputationes), Pope Gregory the Great (Moralia in Job)

2. (Household) economics: Aristotle (Oeconomica)

3. Politics: Aristotle (Politics), Augustine (De civitate Dei), Cicero (De officiis, De re publica, De legibus)

II. Arts

C. Liberal arts

1. Trivium

i. Grammar: Priscian (Prisciani institutionum grammaticalium librorum I-XVI), Donatus (Ars maior, Ars minor), Aristotle (De interpretatione)

ii. Logic / dialectic: Aristotle (Organon: Categories, De interpretatione, Prior Analytics, Posterior Analytics, Topics, Sophistical Refutations), Porphyry (Isagoge), Boethius (Commentaries on Isagoge, Categories, and De interpretatione; De topicis differentiis; In Ciceronis Topica)

a. 1st operation of intellect (simple understanding): Porphyry (Isagoge), Aristotle (Categories)

b. 2nd operation of intellect (judgment / composition and division): Aristotle (De interpretatione)

c. 3rd operation of intellect (reasoning): Aristotle (Prior Analytics, Posterior Analytics, Topics, Sophistical Refutations), Boethius (De topicis differentis, In Ciceronis Topica)

iii. Rhetoric: Aristotle (On Rhetoric), Cicero (De inventione, Catilinarian Orations), Augustine (De doctrina Christiana)

2. Quadrivium

i. Arithmetic: Euclid (Elements VII-X)

ii. Geometry: Euclid (Elements I-VI)

iii. Astronomy: Ptolemy (Almagest)

iv. Music: Boethius (De Institutione Musica)

I. Humanities

C. Poetry

Aristotle (Poetics), Virgil (Aeneid)

D. History

Peter Camestor (Historia scolastica), Augustine (De civitate Dei)