Present Active Infinitive

The present active infinitive names an event without marking a finite subject, person, or number: amāre “to love,” regere “to rule,” audīre “to hear.” “Present” chiefly describes its time relative to a governing verb, while “active” means that its understood or expressed subject is not presented as the patient of a passive form; depending on the verb, that subject may act, experience, possess, or simply be. Those two facts are more reliable than mechanically adding English “to.”

All unlabelled patterns below are normal Classical prose. The infinitive itself does not agree with a subject; clause structure tells the reader who acts and when the action occurs.

Formation

For regular verbs, the present active infinitive is the second principal part. The theme vowel distinguishes the conjugations, especially second-conjugation -ēre from third-conjugation -ere.

Macrons distinguish real vowel quantity: monēre has long ē, but regere has short e. The forms may look identical in unmacronized texts, so the dictionary entry and other principal parts remain essential.

Frequent irregular infinitives must be learned directly: esse “to be,” posse “to be able,” ferre “to carry,” velle “to want,” nōlle “to be unwilling,” mālle “to prefer,” and īre “to go.” Their irregular shapes are lexical, not alternative conjugation endings.

Present Means Simultaneous, Not Necessarily “Now”

In indirect statement, a present infinitive normally represents an event simultaneous with the governing verb. If the report is present, the action is present; if the report is past, the action is simultaneous with that past report.

Latin leaves mūnīre unchanged. English changes “are fortifying” to “were fortifying” because English normally backshifts after a past reporting verb. Calling mūnīre “present” therefore does not mean “present at the time of speaking”; it means “at the same time as dīcit or dīxit.”

Contrast a perfect active infinitive, which marks anterior time:

The difference between mūnīre and mūnīvisse is chronological, not merely an English choice between “to fortify” and “to have fortified.”

Complementary Infinitives: One Understood Subject

Modal and phase verbs such as possum “can,” dēbeō “ought,” volō “want,” incipiō “begin,” and soleō “be accustomed” regularly take a complementary infinitive. Its understood subject is normally the subject of the finite verb.

In Lūcia ... vult, Lucia both wants and writes. There is no accusative subject because the two verbs share their subject. If Lucia wants Marcus to write, Latin uses accusative-and-infinitive or another subordinate construction: Lūcia vult Mārcum scrībere.

English sometimes uses a bare infinitive after modal verbs (“can stay”), sometimes to (“wants to stay”), and sometimes an -ing form (“began writing”). Latin can use the same infinitive shape manēre in all these roles. The construction, not an invariant English equivalent, determines the translation.

More detail appears on Complementary Infinitives.

Accusative and Infinitive: An Expressed Subject

In indirect statement, the infinitive’s subject is accusative. This accusative is a clause-level subject, even though English introduces it with “that” and a nominative pronoun.

The endings dīcere and adesse do not reveal person or number. Tē and plural hostēs, together with context, identify the actors. When the subject of the infinitive is the same person as the subject of the reporting verb, Classical Latin normally uses the reflexive accusative sē: Lūcia dīcit sē venīre “Lucia says that she is coming.”

For the full construction, see Accusative Subject of the Infinitive.

The Infinitive as a Noun-Like Clause

An infinitive can serve as the subject or complement of an impersonal judgment. It remains verbal enough to take its own objects and adverbs, but the whole clause occupies a noun-like slot.

In the second sentence, vērum is the object of dīcere and amīcō īrātō its indirect object. The infinitive has internal syntax even though the entire phrase is the logical subject of difficile est. English often inserts anticipatory “it”; Latin does not need an equivalent pronoun.

See Infinitive as Subject for agreement and impersonal predicates.

Historical Infinitive

Narrative, especially vivid historical writing, can use present infinitives in place of finite imperfect forms: tum omnēs clāmāre, currere, portās pulsāre, “then everyone began shouting, running, and beating on the gates.” This “historical infinitive” is (literary) and often presents rapid or repeated action as a vivid sequence.

Its subject is normally nominative, not the accusative subject of indirect statement. Context and style distinguish the construction. It should be recognized early but not imitated as neutral beginner prose.

Active Form, Active Meaning—and Exceptions

With ordinary active verbs, the subject acts: servus portam aperīre vult “the enslaved man wants to open the gate.” A deponent present infinitive such as loquī has passive morphology but active meaning, so it does not belong to the active-form paradigm on this page. Conversely, a few verbs have lexical meanings that English phrases differently; voice must be identified from Latin morphology, not from whether the English sounds agentive.

The present active infinitive never agrees for gender or number. Forms such as ventūrum esse do show agreement because their participle belongs to the future active infinitive, a different construction.

Common Mistakes

Treating present as absolute time

Using a nominative subject in indirect statement

Confusing second- and third-conjugation quantity

Adding an accusative to a shared-subject complement

Key Takeaways

• Learn the present active infinitive as the second principal part, including vowel quantity and irregular forms.
• “Present” usually means simultaneous with the governing verb, not necessarily present at speech time.
• Complementary infinitives normally share the finite verb’s subject; indirect statement expresses the infinitive’s subject in the accusative.
• The form does not mark person, number, or agreement, so syntax supplies its participants.