A letter from Emperor Gratian to St. Ambrose and Ambrose's reply,
St. Ambrose, Epistle 1
Commentary on St. Ambrose Epistle 1 by Benjamin Suib: revised by Jacques Bailly
Commentary on Gratian's letter by Jacques Bailly

Text of Gratian's Letter

AMBROSIO religioso sacerdoti omnipotentis Dei, GRATIANUS Augustus.
Cupio valde ut quem recordor absentem, et cum quo mente sum, cum eo etiam corpore sim praesenti. Festina igitur ad me, religiose Dei sacerdos, ut doceas doctrinam veram credentem: non quod contentioni studeam, aut velim magis Deum verbis quam mente complecti; sed ut magis aperto pectori revelatio divinitatis insidat. Docebit enim me ille quem non nego, quem fateor Deum ac Dominum esse meum, non ei objiciens quam in me video creaturam, qui Christo nihil me addere posse confiteor: velle tamen ut etiam Patri me commendem filium praedicando. Non ego in Deo verebor invidiam: non me talem laudatorem putabo, qui divinitatem verbis augeam. Ego infirmus et fragilis, quantum possum praedico, non quantum est ipsa divinitas. Rogo te ut mihi des ipsum tractatum quem dederas, augendo illic de Spiritu Sancto fidelem disputationem: scripturis atque argumentis Deum esse convincas. Divinitas te servet per multos annos, parens et cultor Dei aeterni, quem colimus, Iesu Christi!

Text of Ambrose's Response

Beatissimo augusto GRATIANO, et christianissimo principi AMBROSIUS episcopus.
[1] Non mihi affectus defuit, christianissime principum; nihil enim habeo, quod hoc verius et gloriosius dicam: non, inquam, mihi affectus defuit, sed affectum verecundia retardavit, quominus clementiae tuae occurrerem. Revertenti tamen si non occurri vestigio, occurri animo, occurri voto, in quo majora sunt officia sacerdotis. Occurri, dico? Quando enim abfui, quem toto sequebar affectu, cui sensu ac mentibus inhaerebam? Et certe major animorum praesentia est. Tuum quotidianum iter legebam, nocte ac die in tuis castris cura et sensu locatus, orationum excubiis praetendebam: et si invalidus merito, sed affectu sedulus.
[2] Et haec quidem cum pro tua salute deferebamus, pro nobis faciebamus. Nihil hic adulationis est, quam tu non requiris, ego alienam nostro duco officio: sed plurimum gratiae, quam dedisti. Scit ipse nostri arbiter, quem fateris, et in quem pie credis, refici viscera mea tua fide, tua salute, tua gloria: meque non solum officio publico debitas pendere preces, sed etiam amore privato. Reddidisti enim mihi quietem Ecclesiae, perfidorum ora, atque utinam et corda, clausisti: et hoc non minore fidei, quam potestatis auctoritate fecisti.
[3] Nam quid de litteris recentibus loquar? Scripsisti tua totam epistolam manu; ut ipsi apices fidem tuam pietatemque loquerentur. Sic Abraham sua manu quondam vitulum occidit (Gen. XVIII, 7), ut hospitibus epulantibus ministraret: nec in ministerio religioso aliorum adjumenta quaesivit. Sed ille privatus aut Domino et angelis, aut Domino in angelis deferebat: tu, Imperator, dignatione regali honoras infimum sacerdotem. Sed Domino defertur, cum servulus honoratur; ipse enim dixit: Quod uni horum minimorum fecistis, mihi fecistis (Matth. XXV, 10).

Introduction

Flavius Gratianus Augustus, aka Emperor Gratian, lived from 359-383 CE and was emperor in the west from 375 to 383 CE (i.e. from the age of 16 to 24). His younger brother Valentinian II was also emperor in the west from 375 to 392 CE and had his residence at Mediolanum (Milan): Valentinian II was only 4 years old in 375, and died at the age of 17. Theodosius I was emperor in the east. Youthful Gratian, however, is reported to have been more interested in hunting than governing, and so his Bishop Ambrose, among others, had a great deal of the real power in the state. Under Ambrose's influence, in the years after this letter exchange, Gratian passed many measures against the pagans, specifically against the institutions of the Vestal Virgins and the Altar of Victory, thus contributing to the final end of paganism. Gratian was assassinated in 383CE when Magnus Maximus led an insurrection and became Emperor.

Aurelius Ambrose, aka St. Ambrose, lived from around 340 until 397 CE. As a leading ecclesiastical figure in the 4th century, he played a pivotal role in the development of the modern Church and the suppression of the Arian heresy. As Bishop of Milan, at the time de facto capital of the Western Roman Empire, he fostered and maintained close relations with the Imperial leadership. As one of the four original Latin Doctors of the Church (along with St. Augustine, St. Jerome, and Pope Gregory I), Ambrose has had a profound impact on Christian ideology.  St. Augustine of Hippo, in fact, thought poorly of Christian preachers up until he heard the sermons of Ambrose, whose rhetorical talent greatly influenced the young man.  His deep scholarship also greatly influenced the emperor Gratian, to whom this letter is addressed. It is evident from both letters that each man esteems and respects the other.
 
Commentary

Gratian's Letter:

AMBROSIO religioso sacerdoti omnipotentis Dei, GRATIANUS Augustus.
Cupio valde ut quem recordor absentem, et cum quo mente sum, cum eo etiam corpore sim praesenti. Festina igitur ad me, religiose Dei sacerdos, ut doceas doctrinam veram credentem: non quod contentioni studeam, aut velim magis Deum verbis quam mente complecti; sed ut magis aperto pectori revelatio divinitatis insidat. Docebit enim me ille quem non nego, quem fateor Deum ac Dominum esse meum, non ei objiciens quam in me video creaturam, qui Christo nihil me addere posse confiteor: velle tamen ut etiam Patri me commendem filium praedicando. Non ego in Deo verebor invidiam: non me talem laudatorem putabo, qui divinitatem verbis augeam. Ego infirmus et fragilis, quantum possum praedico, non quantum est ipsa divinitas. Rogo te ut mihi des ipsum tractatum quem dederas, augendo illic de Spiritu Sancto fidelem disputationem: scripturis atque argumentis Deum esse convincas. Divinitas te servet per multos annos, parens et cultor Dei aeterni, quem colimus, Iesu Christi!

Augustus: a title granted to Gratian by his father, emperor Valentinianus I, in 367.
ut ... sim: as a nominal ut clause, this is subjunctive, and acts as the object of cupio. The two relative clauses quem... and cum quo... separate the conjunction ut from the rest of its clause.
festina: imperative.
ut doceas: why subjunctive? Note that doceas can take two accusatives, one of the person taught and one of the thing taught to the person.
non quod ... studeam, aut velim: rejected reasons are usually subjunctive.
complecti: what form of the verb complector?
ut ... insidat: this purpose clause is virtually equivalent to the rejected causal clauses in that they all express a reason for action (or not acting). Insidat, like many verbs compounded with in-, takes dative.
ei ... quam in me video creaturam: ei dative with objiciens. creaturam in apposition to quam.
qui ... confiteor: note that the antecedent of qui is the same person as objiciens and the subject of nego. In English, this (and other aspects of this sentence) might be confusing, but Latin cases make the meaning perfectly clear.
velle tamen: another infinitive dependent on confiteor. As with addere posse, the subject is me.
ut commendem: another nominal ut clause: me is acc. object of commendem. An infinitive would have done just as well. praedicando is a gerund in the ablative (of means).
qui ... augeam: relative clause of characteristic, prepared for by talem.
ut ... des ... convincas: nominal ut clauses (an indirect command is a frequent type of nominal ut clause).
servet: jussive subjunctive.
Iesu Christi: genitive in apposition to Dei aeterni.

Ambrose's Letter:

[1] Non mihi affectus defuit, christianissime principum; nihil enim habeo, quod hoc verius et gloriosius dicam: non, inquam, mihi affectus defuit, sed affectum verecundia retardavit, quominus clementiae tuae occurrerem. Revertenti tamen si non occurri vestigio, occurri animo, occurri voto, in quo majora sunt officia sacerdotis. Occurri, dico? Quando enim abfui, quem toto sequebar affectu, cui sensu ac mentibus inhaerebam? Et certe major animorum praesentia est. Tuum quotidianum iter legebam, nocte ac die in tuis castris cura et sensu locatus, orationum excubiis praetendebam: et si invalidus merito, sed affectu sedulus.

non mihi… defuit: desum takes dative.
christianissime principum: partitive genitive with a superlative adj. in the vocative.
quod… dicam: relative clause of characteristic with nihil as antecedent.
hoc verius et gloriosius: abl. of comparison with two comparative advs.
retardavit quominus… occurrerem: with verbs of hindrance or prevention, quominus introduces the subordinate clause that contains the action impeded, always subjunctive following the sequence of tenses.
clementiae tuae: a common way to address royalty, effectively “your grace”.
Revertenti: agrees with implied tibi.
vestigio ... animo ... voto ... toto effectu ... sensu ... mentibus: ablatives of means, to be translated with "in," "by," "with" or some other appropriate preposition, as needed.
Occurri, dico: Latin texts rarely have quotation marks, perhaps because there were none in Latin at the time. In any case, occurri would be in quotation marks if this were English.
quem… sequebar: antecedent tibi (or a te) omitted, the same person as revertenti earlier.
legebam: whereas Latin needs no preposition and just says iter tuum lego, English needs a preposition ("I read about your voyage"). Such asymmetry between English and Latin is frequent: sometimes Latin needs a preposition, sometimes English does.
locatus: modifies subject of legebam and praetendebam.

[2] Et haec quidem cum pro tua salute deferebamus, pro nobis faciebamus. Nihil hic adulationis est, quam tu non requiris, ego alienam nostro duco officio: sed plurimum gratiae, quam dedisti. Scit ipse nostri arbiter, quem fateris, et in quem pie credis, refici viscera mea tua fide, tua salute, tua gloria: meque non solum officio publico debitas pendere preces, sed etiam amore privato. Reddidisti enim mihi quietem Ecclesiae, perfidorum ora, atque utinam et corda, clausisti: et hoc non minore fidei, quam potestatis auctoritate fecisti.

cum: cum temporal takes indicative, unless it refers to the past.
hic: adverb.
nihil… adulationis est: nihil frequently takes a partitive genitive.
ego alienam nostro duco officio: this clause would be connected to what preceeds with "and" in English: here, it is said to be "in asyndeton." Note that duco sometimes means "consider, think, deem." Why is alienam feminine?
plurimum gratiae: another partitive genitive. Understand est as the verb of this clause.
quam dedisti: antecedent omitted: possibly rem.
refici ... pendere: infinitives in indirect speech dependent on scit.
officio ... amore: ablatives of cause.
Redidisti… clausisti: The Emperor Gratian enacted many measures to suppress the pagan religions of old under the direct influence of Ambrose.  Within his lifetime, he issued a decree that all subjects throughout the empire profess their faith in the Nicene Creed (The Church of Rome), appropriated the wealth of the Vestal Virgins, renounced his official title of Pontifex Maximus, and removed the Altar of Victory from the senate house, which had been dedicated in 29 BC by Augustus.  Although thankful for Gratian’s cooperation, it seems that Ambrose would’ve still advised harsher consequences for the “perfidi”.
utinam: normally takes subjunctive. Supply clausivisses.
minore ... auctoritate: ablative of cause: auctoritate goes with both fidei and potestatis.

[3] Nam quid de litteris recentibus loquar? Scripsisti tua totam epistolam manu; ut ipsi apices fidem tuam pietatemque loquerentur. Sic Abraham sua manu quondam vitulum occidit (Gen. XVIII, 7), ut hospitibus epulantibus ministraret: nec in ministerio religioso aliorum adjumenta quaesivit. Sed ille privatus aut Domino et angelis, aut Domino in angelis deferebat: tu, Imperator, dignatione regali honoras infimum sacerdotem. Sed Domino defertur, cum servulus honoratur; ipse enim dixit: Quod uni horum minimorum fecistis, mihi fecistis (Matth. XXV, 10).

loquar: deliberative subjunctive.
tua ... manu: i.e. Gratian himself wrote it, not an amanuensis.
ut… loquerentur: result clause in secondary sequence, dependent on scripsisti.
(Gen. XVIII,7): 6 And Abraham hastened into the tent unto Sarah, and said, Make ready quickly three measures of fine meal, knead it, and make cakes upon the hearth.
7 And Abraham ran unto the herd, and fetcht a calf tender and good, and gave it unto a young man; and he hasted to dress it.
8 And he took butter, and milk, and the calf which he had dressed, and set it before them; and he stood by them under the tree, and they did eat.
ut… ministraret: purpose clause in secondary sequence, dependent on occidit; ministro takes the dative.
epulantibus: gerund of epulor in the dative plural.
Tu, Imperator… sacerdotem: Sentential object of deferebat.
(Matth. XXV, 10): The verse quoted here is Matth. XXV, 40 in the King James Version:
“40 And the King shall answer and say unto them, Verily I say unto you, Inasmuch as ye have done it unto one of the least of these my brethren, ye have done it unto me.”

Bibliography:
Text of Ambose letter :  <http://www.thelatinlibrary.com/ambrose/epistvaria.html>
Text of Gratian letter: Sancti Ambrosii Mediolanensis Episcopi Opera, tome 4, Paris, Societas Typographica, 1621.
Bible Verses: <https://www.biblegateway.com>

Vocabulary
Abraham (biblical patriarch)
absens, absentis, absent, not present
absum, to be absent
addo, addere, addidi, additum, bring to, add to
adiumentum, -i, n., help
adulatio, -onis f., flattery
aeternus, -a, -um, eternal, everlasting
affectus, -us, m., affection
alienus, -a, -um, contrary, unfavorable
angelus, -i, m., angel
animus, -i, m., spirit
apertus, -a, -um, open, opened
apices, -um, m., letters (of the alphabet)
arbiter, -tri, m., lord, master
argumentum, -i, n., proof., argument
auctoritas, -atis, f., power, authority
augeo, augere, auxi, auctus, increase, strengthen, magnify, exalt, extol
castra, -orum, n., military camp
certe, surely
christianus, -a, -um, Christian
claudo, claudere, clausi, clausus, to close
clementia, -ae, clemency
colo, colere, colui, cultus, worship, cultivate
commendo (1), commit to one’s care, commend to
complector, amplecti, amplexus, embrace
confiteor, confiteri, confessus sum, confess, admit
contentio, -onis, f., argument, struggle
convinco, convincere, convici, convictus, prove, show clearly
cor, cordis, n., heart
corpus, -oris, n., body
creatura, -ae, f., a creation, creature
credo, credere, credidi, creditum, believe; trust
credo, to believe
cultor, -oris, m., worshiper
cupio, cupere, cupivi, cupitum, desire, want
cura, ae, f., care, concern
defero, deferre, detuli, delatus, to bestow, present
desum, deesse, defui, to lack (+dat)
dico, to say
dies, diei, m., - day
dignatio, onis, f., esteem
disputatio, -onis, f., argument, discussion, debate
divinitas, -atis, f., divinity
do, dare, dedi, datus, to give
doceo, docere, docui, doctus, teach,
doctrina, -ae, f., teaching, learning, instruction
dominus, -i, m., lord, master, God
duco, to esteem
ecclesia, The Church
enim, for
epistola, -ae, f., letter
epulor (1), to feast
excubiae, -arum, f., watching
facio, to do, make
fateor, fateri, fassus sum, confess, acknowledge, own
festino (1), hurry
fidelis, -e, faithful
fides, -ei, f., faith
filius, -i, m., son
fragilis, -e, breakable, fragile
gloria, -ae, f –glory
gloriosus, -a, -um, full of glory
gratia, -ae, f –thanks
habeo, habere, habui, to have
honoro (1), to honor
hospes, -itis, m., guest
igitur, therefore
imperator,-oris, m., Emperor
infimus, -a, -um, lowest
infirmus, -a, -um, weak
inhaereo, haesi, haesum, to be firmly attached to
inquam, inquit, to say
insido, insidere, insedi, (+ dat.), settle in, take possession of
invalidus, -a, -um, weak, ineffectual
invidia, -ae, f., envy, spite, hatred
ipse, ipsa, ipsum, himself., herself., itself
iter, itineris, n., journey
laudator, -oris, m., flatterer, praiser
lego, to read of., study
litterae, -arum, f., letters
loco, to place
loquor, to say
maior, -ius, greater
manus, -us, f., hand
mens, mentis, f., mind
meritum, -i, n., service, favor, benefit
minimus, -a, -um, smallest
ministerium, -i, n., service
ministro (1), to serve (+dat)
minor, -us, minor, lesser, smaller
nego (1), deny
nihil, nothing (indec.)

nox, noctis, f , night

objicio, objicere, objeci, objectus, (+ dat.), throw before, place in the way of., oppose, present to, object to
occido, - to kill

occuro (3), to meet (+dat)

officium, -i, n., duty
omnipotens, omnipotentis, omnipotent
oratio, orationis, f., prayer

os, oris, n., mouth
parens, -entis, m/f., parent
pectus, -oris, n., chest, breast
pendeo, to hang down

perfidus, -a, -um, unfaithful

pietas, -atis, f., piety
pius, -a, -um, faithful

plurimus, -a, -um, many

potestas, -atis, f., ability

praedico (1), proclaim
praesens, -ntis, being present, at hand

praesens, praesentis, present
praetendo, praetendere, praetendi, praetentum, to stretch forth

preces, -um, f., prayer

princeps, -ipis, prince (lit. first person)

privatus, -a, -um, private

publicus, -a, -um, public
puto (1), think
quaero, to look for
quando, when

quantum, adv., as much
quies, quietis f., quiet

quominus, so that (used after verbs of hindrance with a subj.)

quondam, formerly

quotidianus, -a, -um, daily, day by day
recens, -ntis, recent
recordor (1), think about, be mindful of., recall
reddo, to restore

reficio, to restore, repair
regalis, -e, kingly
religiosus, -a, -um, devout, pious
religiosus, -a, -um, religious
requiro, to need

retardo (1), to slow down

revelatio, -onis, f., uncovering, laying bare, revelation
reverto, to return
rogo (1), ask
sacerdos, sacerdotis, m., priest
salus, salutis, f., health
scio, to know
scribo, scribere, scripsi, scriptum, write
scriptura, -ae, f., scripture, writing
sedulus, -a, -um, sedulous, attentive
sensus, -us, m., emotion, sense
sequor, sequi, secutus sum, to follow

servo (1), preserve, save
servulus, -i, m., young slave

solum, only
studeo, studere, studui, be diligent about, study, take pains about
totus, -a, -um, total
tractatus, -us, m., treatise
unus, -a, -um – one
utinam, if only
valde, very much, greatly
verecundia, -ae, modesty
vereor, vereri, veritus sum, fear
verus, -a, -um, true
vestigium, -i, n., track, footprint
viscer-a, -um, pl., , heart, center, life, internal organs
vitulus, -i, m., calf
votus, -i, m –prayer