Coepi, Incipio, and Desino with Infinitives | Latin Grammar

Latin commonly marks the beginning or end of an activity with coepī, incipiō, or dēsinō plus a complementary infinitive. Scrībere coepit means “she began to write,” scrībere incipit “she begins to write,” and scrībere dēsinit “she stops writing.” The infinitive supplies the activity; the finite verb supplies the subject, tense, person, number, and mood.

This is the same-subject pattern surveyed under Complementary Infinitives, with extra complications caused by defective coepī and passive attraction.

The three verbs are not interchangeable pieces of vocabulary. Coepī is defective and normally exists only in the perfect system, even though its meaning is simply “began.” Incipiō supplies a full present system and can also mean “undertake.” Dēsinō has a normal present system and expresses stopping or leaving off. Unless marked otherwise, the examples are (neutral Classical prose) with pedagogical macrons.

The three lexical entries

Verb	Principal parts	System available	Core use
coepī	coepī, coepisse, coeptus	perfect system; present forms are archaic or exceptional	began, have begun
incipiō	incipiō, incipere, incēpī, inceptum	full regular third-iō system	begin, commence, undertake
dēsinō	dēsinō, dēsinere, dēsiī, dēsitum	full third-conjugation system	cease, stop, leave off

The principal parts prevent two predictable mistakes. First, present “begins” cannot normally be made from coepī: use incipit. Second, the perfect of incipiō uses the stem incēp-; it is incēpit, not incipīvit. Classical authors often use the common defective coepit where English simply says “began,” while incēpit remains a genuine form of incipiō.

Orātor loquī incipit; omnēs statim silent.

The speaker begins to talk; everyone immediately falls silent.

Post breve silentium orātor iterum loquī coepit.

After a brief silence, the speaker began to talk again.

Ubi nox vēnit, mīlitēs pugnāre dēsiērunt.

When night came, the soldiers stopped fighting.

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Do not let the form coepit tempt you into translating it as “has begun” every time. It is morphologically perfect, but the Latin perfect can narrate a simple past event: “began.”

The complementary infinitive shares its subject

With an active or semantically active infinitive, the finite verb and infinitive normally share one subject. There is no accusative subject as in indirect statement.

Lūcia epistulam scrībere coepit.

Lucia began to write the letter.

Discipulī difficiliōra intellegere incipiunt.

The students are beginning to understand more difficult material.

Senex post sōlis occāsum labōrāre dēsinēbat.

The old man used to stop working after sunset.

In Lūcia ... coepit, nominative Lūcia is the subject of both beginning and writing. Epistulam is the object of scrībere, not of coepit in the relevant analysis. A deponent infinitive behaves the same way semantically despite its passive-looking form.

Legātī prīmā lūce proficīscī coepērunt.

The envoys began to set out at dawn.

Proficīscī is a present deponent infinitive with active meaning. It does not trigger passive coeptī sunt, because the embedded activity is not passive.

Tense and aspect: onset is an event of its own

The finite verb locates the beginning or cessation. The present infinitive normally gives an action simultaneous with that boundary; it does not express present time independently.

Latin	Finite analysis	Natural value
facere incipit	present indicative	begins/is beginning to do
facere incipiēbat	imperfect indicative	was beginning/used to begin to do
facere coepit	perfect indicative	began to do
facere coeperat	pluperfect indicative	had begun to do
facere dēsinet	future indicative	will stop doing
facere dēsinat	present subjunctive	may/should stop doing, according to syntax

Iam pontem facere coeperant cum hostēs appropinquāvērunt.

They had already begun building the bridge when the enemy approached.

Monet eōs ut inter sē querī dēsinant.

He warns them to stop complaining among themselves.

In the first sentence pluperfect coeperant places the onset before the enemy's approach. In the second, ut after monet requires subjunctive dēsinant. The following infinitives remain present because the building and complaining are the activities being entered or left, not separately timed reported statements.

Coepī has no ordinary present system

Classical coepī is formally a perfect, with forms such as coepistī, coepit, coepimus, coepērunt; pluperfect coeperam; future perfect coeperō; perfect subjunctive coeperim; and infinitive coepisse. To express present-time onset, Latin normally uses incipiō.

Nunc rem intellegere incipiō; herī eam tantum suspicārī coepī.

Now I am beginning to understand the matter; yesterday I only began to suspect it.

English learners sometimes reason that because coepī looks like a perfect, a present coepiō must exist beside it. A few archaic forms under a related headword occur, but they are not a productive Classical prose paradigm. Use incipiō rather than manufacturing forms.

The future active participle coeptūrus is available (marked/formal), but ordinary future meaning can usually be expressed more directly with incipiam “I shall begin.”

Passive infinitives and attraction into the passive

With a genuinely passive infinitive, Latin often puts coepī itself into a passive-looking form: an agreeing coeptus, -a, -um plus sum. English still translates “began to be ...”.

Urbs ab hostibus oppugnārī coepta est.

The city began to be attacked by the enemy.

Duae nāvēs in portū reficī coeptae sunt.

Two ships began to be repaired in the harbor.

Nominative urbs controls feminine singular coepta; duae nāvēs controls feminine plural coeptae. The passive infinitive remains oppugnārī or reficī. This is sometimes called passive attraction: the passive orientation of the infinitive is reflected in the finite beginning verb.

The active alternative urbs oppugnārī coepit is also attested. The agreeing passive is a characteristic Classical pattern, not an absolute mechanical rule. With dēsinō, a comparable dēsitus est construction occurs:

Veterēs ōrātiōnēs legī dēsitae sunt.

Old speeches ceased to be read.

Because this pattern can feel alien to English speakers, preserve its layers: ōrātiōnēs is nominative plural, legī is present passive infinitive, and dēsitae sunt agrees with the nominative subject. Do not interpret dēsitae as “were abandoned” independently of the infinitive.

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Passive attraction applies when the infinitive is truly passive. A deponent such as proficīscī has active meaning, so write legātī proficīscī coepērunt, not coeptī sunt.

Incipiō with an object versus an infinitive

Incipiō can directly take a noun meaning an undertaking: bellum incipit “he begins a war,” iter incipit “he begins a journey.” With an infinitive, it marks entry into the activity: pugnāre incipit “he begins to fight.” English can use “begin” in both, but Latin syntax is visibly different.

Cōnsul bellum incēpit; mīlitēs autem pugnāre nōndum coeperant.

The consul began the war, but the soldiers had not yet begun to fight.

Perfect incēpit is transitive here and takes bellum. Pluperfect coeperant is completed by pugnāre. Neither construction requires ut.

Register and pragmatic choice

All three verbs are normal Classical vocabulary. Coepī is especially frequent for a bounded narrative onset; incipiō is indispensable in the present system and useful when something is undertaken; dēsinō can neutrally report cessation or function as a direct command, dēsine! “stop!” In invective or urgent dialogue, dēsine may sound sharp (informal/rhetorical); the grammar itself is not vulgar.

Cicero urges Catiline's associates (formal oratory):

Desinant furere ac proscriptiones et dictaturas cogitare.

Let them stop raging and planning proscriptions and dictatorships. (Cicero, In Catilinam 2.20; source spelling reproduced without added macrons.)

The finite jussive subjunctive dēsinant governs coordinated infinitives furere and cōgitāre.

Common Mistakes

1. Inventing a normal present of coepī

❌ Nunc scrībere coepiō.

Incorrect in ordinary Classical prose — coepī lacks a productive present system.

✅ Nunc scrībere incipiō.

Now I am beginning to write.

2. Building a perfect from an invented present stem

❌ Herī loquī coepīvit.

Incorrect — coepīvit is invented from a present stem that defective coepī does not use.

✅ Herī loquī coepit.

Yesterday he began to speak.

3. Adding ut before a complementary infinitive

❌ Lūcia coepit ut scrīberet.

Incorrect for the ordinary same-subject meaning 'Lucia began to write.'

✅ Lūcia scrībere coepit.

Lucia began to write.

4. Ignoring agreement in passive attraction

❌ Duae nāvēs reficī coeptum est.

Incorrect — personal nāvēs requires an agreeing feminine plural participle and plural auxiliary.

✅ Duae nāvēs reficī coeptae sunt.

Two ships began to be repaired.

5. Treating a deponent infinitive as semantically passive

❌ Legātī proficīscī coeptī sunt.

Incorrect for 'the envoys began to set out' — proficīscī is deponent and active in meaning.

✅ Legātī proficīscī coepērunt.

The envoys began to set out.

Key Takeaways

Use incipiō for a full present system, defective coepī for the perfect-system verb “began,” and dēsinō for cessation. Their complementary infinitive normally shares the finite verb's subject and follows without ut. With a genuinely passive infinitive, coeptus sum and sometimes dēsitus sum can agree with the nominative subject; deponent infinitives do not trigger that attraction.

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