Peter Lombard’s







On the Trinity and Unity of God


An English Translation with the Latin text in parallel

According to the Quaracchi Edition of 1882

 This is the great “Summa” of Medieval Theology, which was commented on by such Doctors of the Church
as Sts. Thomas Aquinas, Bonaventure, Albert the Great,
and such eminent theologians as Blesseds John Duns Scotus, Peter of Tarentaise, and Dionysius the Carthusian.


An Introduction to the English Translation of This Work



The Franciscan Archive

is currently sponsoring a project for the publication of an English Translation
of this great work of Master Peter Lombard.
See The Commentary Project for more information.
The parts currently published are as follows:


DE  DEI  UNITATE  ET  TRINITATE                                    

What follows is the First Complete English translation of the First Book of Sentences (© 2006), which is now available on CD-Rom, from The Franciscan Archive.  You can read more about this translation at The Commentary Project.


The Prologue to the Book of Sentences

Chapter 1: Every doctrine concerns things and/or signs.
Chapter 2: On the things which one is to enjoy and/or to use, and on those who use and enjoy
Chapter 3: What is it to use and to enjoy?

Chapter 1: On the Trinity and Unity.
Chapter 2: What was the intention of those writing of the Trinity?
Chapter 3: What order is to be observed, when dealing with the Trinity?
Chapter 4: On the testimonies of the Old Testament, by which the Mystery of the Trinity is declared.
Chapter 5: On the testimonies of the New Testament, pertaining to the same.

PART I, Chapter 1: On the cognition of God through the creatures, in which the vestige of the Trinity appears.
PART II, Chapter 2: On the image and similitude of the Trinity in the human soul.
Chapter 3: On the similitude of the creating and created trinity.
Chapter 4: On the unity of the Trinity.

Chapter 1: Whether God the Father begot Himself God?
Chapter 2: Whether the Trinity may be predicated of the one God, as the one God of the Three Persons?

Chapter 1: Whether the Divine Essence begot the Son, and/or is begotten by the Father,
and/or whether the Son is born from It, and/or the Holy Spirit proceeds from It?
Chapter 2: That the Son is not from nothing, but some someone or thing,
non however from matter, just as also is the Holy Spirit.
Chapter 3: Why the Word of the Father is called the Son of His Nature.

Chapter Sole: Whether the Father begot the Son by will, or by necessity; and whether God is willing and/or unwilling.

Chapter 1: Whether the Father could and/or willed to beget the Son.
Chapter 2: Or whether there is some power in the Father that can beget the Son, which is not in the Son.

PART I, Chapter 1: On the truth and property of the Divine Essence.
Chapter 2: On the incommutability of the same.
PART II, Chapter 3: On the simplicity of the same.
Chapter 4: On the corporal and spiritual creature, in what manner it be multiple, and not simple.
Chapter 5: That God, though He be simple, is nevertheless spoken of in a multiple manner.
Chapter 6: That the simplicity of God is subject to none of the predicaments.
Chapter 7: That God is abusively said to be a substance.
Chapter 8: That there is not in God anything that is not God.

Chapter 1: On the distinction of the Three Persons.
Chapter 2: On the coeternity of the Father and of the Son.
Chapter 3: On the ineffable and intelligible manner of the generation.
Chapter 4: Whether there ought to be said: God always is begotten, and/or always has been begotten.
Chapter 5: On the objections of the heretics striving to prove, that the Son is not coeternal to the Father.

Chapter 1: That the Holy Spirit is properly said to be the Love of the Father and of the Son.
Chapter 2: That the same names are properly and universally accepted.
Chapter 3: That the Holy Spirit, just as He is common to the Father and to the Son, so has a common proper name.

Chapter 1:  That the Holy Spirit proceeds from the Father and the Son, whom, however, the Greeks disavow to proceed from the Son.
Chapter 2:  On the Agreement of the Latins and the Greeks in sense, and their difference in words.

Chapter I:  Whether the Holy Spirit proceeds before and/or more fully from the Father than from the Son.

Chapter II: That the Holy Spirit is said principally and properly to proceed from the Father.



Chapter I:  Why is the Holy Spirit, since he is from the Substance of the Father, not said to be begotten, but only proceeding?
Chapter II:  Why is the Son said to proceed, when the Holy Spirit is not said to be begotten?
Chapter III:  That a mortal cannot distinguish between the generation of the Son and the procession of the Holy Sprit.
Chapter IV:  Whether the Holy Spirit ought to be said to be unbegotten, since He is not begotten.



Chapter I:  On the twin procession of the Holy Spirit, the temporal and eternal.

Chapter II:  That not only the gifts of the Holy Spirit, but also the Holy Spirit Himself is given and sent to men.

Chapter III:  Whether or not holy men could give the Holy Spirit.




PART I, Chapter I:  That the Holy Spirit is given by Himself, and the Son is sent by Himself

Chapter II:  In what manner is the mission of Each to be understood.

Chapter III:  That the Son has also been sent by the Holy Spirit.

Chapter IV: That the Son has also been given by Himself.

Chapter V: In what manner this must be understood:  I have not come on My own.

PART II, Chapter VI: Whether the Son has been sent only once, or often.

Chapter VII: On the two manners of the Son’s mission.

Chapter VIII: That according to one manner He has been sent once, according to the other often; and according to one manner He is said (to have been) sent into the world, according to the other He is not.

Chapter IX: For what reason is the Father not said to be sent.

Chapter X:  That the Son and the Holy Spirit are not as ones lesser than the Father, because They have been sent. 




Chapter I:  On the Mission of the Holy Spirit, which comes to be in two manners, visibly and invisibly.

Chapter II:  That the Son, according to which He is Man, is not merely less than the Father, but also less than the Holy Spirit.




PART I,  Chapter I:  That the Holy Spirit is the charity, by which we love God and neighbor.
Chapter II:  That fraternal love is God, and not the Father and/or the Son, but only the Holy Spirit.
Chapter III:  That this verse:  ‘God is charity’, has not been said in the manner of a cause, as this verse:  ‘Thou art my patience and my hope.’
Chapter IV:  In what manner the Holy Spirit is sent and/or given to us.
PART II,  Chapter V:  Whether the Holy Spirit is increased in a man, and/or is less and more had and/or given, and whether He is given to one having and to one not having.
Chapter VI:  That some say, that the charity of God and neighbor is not the Holy Spirit.



Chapter I:  Whether it must be conceded, that gifts are given through a gift.
Chapter II:  Whether the Holy Spirit is said to be ‘a gift’ for the same reason, that He is said to be given or granted.
Chapter III:  That just as the Son by being born accepted not only, ‘to be the Son’, but also ‘to be the Essence’, so the Holy Spirit by proceeding accepted not only, ‘to be a gift’, but ‘to be the Essence’.
Chapter IV:  That the Holy Spirit is said to be a ‘gift’ and a ‘granted’ according to the two aforesaid manners of procession, who, according to which He is a gift, is referred to the Father and the Son, according to which a given, to Him who gives and to those to whom He is given.
Chapter V:  Whether the Son, since He has been given to us, can be said to be ‘ours’, as the Holy Spirit is.
Chapter VI:  Whether the Holy Spirit is referred to Himself.


PART I,  Chapter I:  On the equality of the Three Persons.
Chapter II:  That eternity and magnitude and power in God is one, even if they seem to be diverse.
Chapter III:  That none of the Persons exceeds the Other in magnitude, because one Person is not greater than the Other, nor are Two something more than One, nor Three than Two and/or One.
Chapter IV:  In what manner is the Father said to be in the Son an the Son in the Father and the Holy Spirit in Each.
PART II, Chapter V:  That None of the Persons is a part in the Trinity.
Chapter VI:  For what reason are the Three Persons said to be most highly one.
Chapter VII:  When we say, that the Three Persons are the one Essence, neither do we predicate It as a genus of species nor as a species of individuals, because it is not that the Essence is a genus and a Person a species, and/or the Essence a species and the Persons individuals.
Chapter VIII:   That neither according to a material cause are the Three Persons said to be the one Essence.
Chapter IX:  Nor are the Three Persons thus said to be the one Essence, as three men are one in nature and/or of one nature.
Chapter X:  Whether the Three Persons differ in number, who have been distinguished by properties.
Chapter XI:  For what reason are the Three Persons together not something greater than One (Person).
Chapter XII:  That God is not to be said to be “threefold”, but “triune”.


Chapter I:  That None of the Persons exceeds Another in power.
Chapter II:  That the Son is no less able than the Father.
Chapter III:   On the objections of heretics against this, and the response of Catholics.


Chapter I:  In what manner can there be said:  ‘the Father alone’, and/or ‘the Son alone’ and/or ‘the Holy Spirit alone’, since They are inseparable.
Chapter II:  Whether there ought to be said:  ‘the Father alone is God’, and/or ‘the Son alone is God’, and/or ‘the Holy Spirit alone is God’; or whether, ‘the Father is the only God’, ‘the Son is the only God’, ‘the Holy Spirit is the only God’.
Chapter III:  In what manner is the Trinity said (to be) God alone, since He is with the spirits and the souls.


Chapter I:  On the difference of the names, which we use speaking of God.
Chapter II:  On those which convene with God temporally and are said relatively.
Chapter III:  On this name which is “Trinity”.
Chapter IV:  On those which properly pertain to the each Person, and on those which signify the Unity of the Essence.


Chapter I: On this name which is “Person”, since it is said according to substance, it is accepted not singularly, but plurally in the Most High.
Chapter II:  By what necessity has there been said by the Latins “Three Persons”, and by the Greeks “Three Hypostases and/or Substances”.
Chapter III:  For what reason do we not say that the Father and the Son and the Holy Spirit are “Three Gods”,  since we do say that they are “Three Persons”.
Chapter IV:  Why do we not say “Three Essences”, since (we do say) “Three Persons”.
Chapter V:  That in the Trinity there is not a diversity and/or singularity and/or solitude, but a Unity and a Trinity and distinction and identity.
Chapter VI:  That God ought not be said (to be) “manifold”.


Chapter Sole:  What is signified by these names:  “one”, “two”, “three”, “triune” and/or “trinity”, “many” and/or “plurality”, “distinction” and/or “distinct”, when we use them, speaking of God.


Chapter I:  What is signified by this name “Person” in the plural number, that is, when there is said “Persons”.
Chapter II:  On the threefold acceptance of this name “Person” in the Trinity.
Chapter III:  Out of which sense is there said:  One, the Person of the Father, Another, the Person of the Son, Another, that of the Holy Spirit; or the Father is one in person, the Son another, the Holy Spirit another.


Chapter I:  On this name “hypostasis”.
Chapter II:  On the properties of the Persons and on the names relative to these.
Chapter III:  That not all names are said of God according to substance; for certain ones are said according to relation, however nothing is said according to accident.
Chapter IV:  For what reason is it said that it is proper to the Only-Begotten, to be the Son of God, since even men are the sons God.
Chapter V:  That a man is said to be a “son” of the Trinity, and the Trinity, the “father” of men.
Chapter VI:  That the Holy Spirit is said to be “the Gift” by the same property, by which He is said to be “the Holy Spirit”, and in each manner relatively to the Father and the Son.
Chapter VII:  Whether the Father and/or the Son and/or the Trinity Itself can be said to be a “holy spirit”.
Chapter VIII:  That not all the names, which are said relatively, respond, according to their terms, to one another in reverse.


PART I, Chapter I:  What are those properties, by which the Persons are distinguished.
Chapter II: 
That it is not entirely the same to say, that He is the Father and that He has begotten and/or has a Son.
Chapter III:  That the properties determine the Hypostases, not the Substance, that is, the Nature.
PART II:  That there are other names for the Persons, which also signify Their personal properties.
Chapter IV:  On the general rule for those which regard themselves, and for those which are said relatively.
Chapter V:  Or whether according to substance there is said “God from God”, and sayings of this kind.


Chapter I:  That there are not only three properties of the Persons.
Chapter II:  Whether the Father alone ought to be said to be “not-begotten” and/or “not-a-son”, just as He is said to be “unbegotten”.
Chapter III: On the property, which “unbegotten” notes.
Chapter IV:  The response of St. Ambrose against the Arians concerning the Unbegotten.
Chapter V:  Whether ‘to be a father’ and ‘to be a son’ is diverse.
Chapter VI:  Whether wisdom is said to be begotten according to relation, and/or according to substance.
Chapter VII:  On “image”.


Chapter I:  On principium.
Chapter II:  That from eternity the Father is a principle and the Son, but not the Holy Spirit.
Chapter III:  In what manner the Father is the principle of the Son, and He with the Son the principle of the Holy Spirit.
Chapter IV:  Whether the Father and the Son are the principle of the Holy Spirit according to the same notion.


Chapter I:  On those names, which are said of God temporally and relatively according to an accident, which accedes not to God, but to creatures.
Chapter II:  Whether the Holy Spirit is said to have been given and/or granted relatively to Himself, since He is given by Himself.


PART I, Chapter I:  Whether the Son is said to be “equal” and/or “similar” to the Father according to substance.
PART II, Chapter II:  On the sentence of Saint Hilary, by which he shows the names proper to the Persons in the Trinity.
Chapter III:  For what reason is “unity” attributed to the Father.
Chapter IV:  For what reason are the Father and the Son said to be unum and/or unus Deus, but not unus.
Chapter V:  Why there is said to be an equality in the Son.
Chapter VI:  Why in the Holy Spirit there is said to be virtue, concord and/or a connection.


Chapter I:  Whether the Father and/or the Son love by that love, which proceeds from Each, that is, by the Holy Spirit.
Chapter II:  Whether the Father is wise by the Wisdom, which He begot.
Chapter III:  Whether the Son is wise by Himself and/or through Himself.
Chapter IV:  Whether there is only one Wisdom of the Father.
Chapter V:  Just as in the Trinity there is the Love, which is the Trinity, and yet the Holy Spirit is the Love, which is not the Trinity, nor for that reason are there two Loves; so also concerning Wisdom.
Chapter VI:  For what reason is the Father not said (to be) wise by the Begotten Wisdom, just as He is said (to be) loving by the Love, which proceeds from Him.


Chapter I:  Whether the properties of the Persons are the Persons Themselves, and/or the Divine Ousia.
Chapter II:  In what manner can the properties be in the Nature of God, and not determine It.


Chapter I:  On the words of St. Hilary, by which he seems, according to the intelligence of the depraved, to say, that the Divine Nature and the Thing of the Nature is not the Same, and that God and what God is, is not the Same.
Chapter II:  Whether there can be said, “one God of three Persons”, as there is said, “one essence of three Persons”, and whether there can be said “three Persons of one God”, as there is said “three Persons of one essence”.
Chapter III:  That power, wisdom, and goodness are sometimes referred in Scripture to the Persons distinctly.
Chapter IV:  For what reason is power attributed to the Father, wisdom to the Son, goodness to the Holy Spirit, since there is one Power, Wisdom, and Goodness of the  Three.
Chapter V:  On this name homoousion, where is it received in authority, and what does it signify.


Chapter I:  On God’s knowledge, foreknowledge, providence, disposition and predestination.
Chapter II:  What does His foreknowledge and/or foresight concern?
Chapter III:  What does His disposition concern?
Chapter IV:  What does His predestination concern?
Chapter V:  What does His providence concern?
Chapter VI:  What does His wisdom and/or knowledge concern?
Chapter VII:  Whether foreknowledge and/or disposition could belong to God, if there were no future things?
Chapter VIII:  That God’s knowledge concerns things temporal and eternal.
Chapter IX:  In what manner are all said to be “in God” and to be “life in Him”?


Chapter I:  Whether all ought to be said to be in the God’s Essence, as they are said to be in God’s Cognition and/or foreknowledge.
Chapter II:  By what reckoning are good things said to be in God, and not evil ones.
Chapter III:  Whether it is the same that all are “from God” and “through Him” and “in Him”.
Chapter IV:  That all are in Any of the Three both through Him and in Him.
Chapter V:  That not all which are ex Deo, are also de ipso.


PART I, Chapter I:  In what manners God is said to be in things.
Chapter II:  That God does not dwell, wheresoever He is, but the other way around.
Chapter III:  Where God was, before there was a creature.
Chapter IV:  That God, though He is in all things essentially, yet is not completely befouled with sordid things.
PART II, Chapter V:  Since God is everywhere and always, yet does not belong to a place, He is moved neither according to place nor according to time.
Chapter VI:  In what manners is something said to belong to a place, and/or be circumscribable.
Chapter VII:  What is it to be changed according to time.
Chapter VIII:  Whether created spirits belong to a place and are circumscribable.
Chapter IX:  That God is everywhere without local movement.


Chapter I:  Whether the Knowledge and/or Foreknowledge of God is the cause of things, and/or the other way around.
Chapter II:  Whether God’s Foreknowledge can fail.


Chapter I:  Whether God’s Knowledge can be increased and/or lessened and/or in any manner be changed.
Chapter II: 
Whether God can newly either know in time and/or foreknow something.
Chapter III:  Whether God can know more, than He knows.
Chapter IV:  That God, both always and together, knows all.


Chapter I:  Whether anyone predestined can be damned, and/or anyone reprobate be saved.
Chapter II:  What is God’s reprobation, and in whom is it considered, and what is the effect of predestination?


Chapter I:  Whether there is anything meriting obduration and/or mercy.
Chapter II:  On the various opinions of carnal men on this.
Chapter III:  Whether those which God once knows and/or foreknows, He always knows and foreknows, and always had known and had foreknown.


Chapter I:  On the Omnipotence of God, for what reason is He said to be “omnipotent”, since we can do many things, which He Himself cannot do.
Chapter II:  In what manner is God said to be able to do all things.
Chapter III:  That the Omnipotence of God is considered according to two acts.


Chapter I:  An invective against those who say, that God can do nothing, but what He wills and does.


Chapter I:  Whether God can make something better, than He has made it, and/or in another and/or better manner, than He has.
Chapter II:  Whether God can always do everything which He could do.


Chapter I:  On God’s Will, which is God’s Essence, and on Its signs.
Chapter II:  That though for God it is the same to will as to be, yet God cannot be said to be all which He wills.
Chapter III:  On the understanding of these expressions:  “God knows, and/or God Wills”, “God knows all and/or wills something”.
Chapter IV:  That God’s most highly Good Will is the Cause of all which naturally are, the cause of Which is not to be sought, because It is the First and Most High Cause of all.
Chapter V:  In what manners is God’s “will” accepted.
Chapter VI:  That God’s preception, prohibition, permission, counsel, and operation are sometimes understood by the name of “will”.
Chapter VII:  That God wills that by all there be done those things which He precepts, and/or not be done those which He prohibits.


Chapter I:  That the Will of God, which He Himself is, can be cancelled in nothing.
Chapter II:  In what manner is this to be understood:  “I willed to gather thy children together, and thou wouldst not”, and this:  “He who wills all men to come to be saved”.
Chapter III:  Whether evils come to be with God being willing and/or unwilling.
Chapter IV:  In what manner is this saying of St. Augustine to be understood:  “It is good that evils come to be”.
Chapter V:  On the multiple acceptation of the “good”.
Chapter VI:  That evils have value for the university of things.
Chapter VII:  That the cause, that man is worse, is not in God.


Chapter I:  That the Will of God concerning a man is fulfilled, whithersoever he turns himself.
Chapter II:  In what sense certain things are said to be done “against” the Will of God.
Chapter III:  For what reason did God precept to all to do good and avoid evil, but does not will that this be fulfilled by all.


Chapter I:  That man sometimes with good will wills something other than God wills, and with bad will sometimes wills the same which God wills.
Chapter II:  That God’s Will is fulfilled through the evil wills of men.
Chapter III:  Whether it pleased holy men, that Christ would suffer and die.
Chapter IV:  Whether we ought to will the sufferings of the Saints.




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