Gerundives and gerunds are two forms in Latin that are made from verbal stems.  The Latin gerundive is a passive verbal adjective that conveys necessity or obligation.  For example, in Latin it is possible to say,

Apollonius litteram legendam ad Africam misit.
Apollonius sent to Africa a letter that must be read.

English does not have an equivalent construction, but uses a subordinate clause to convey the necessity of a verbal idea.  However, Latin can convey this with the gerundive. Note that gerundive legendam is made from the verb stem lego, legere but functions like an adjective by modifying litteram in gender, number, and case.  

Gerunds are verbal nouns.  They are actions (typically expressed with verbs, eg. “to write”) that are used as nouns (“writing”).  Gerunds are found both in Latin and in English. For example:

Aelia artem scribendi cognoscit.
Aelia learns the art of writing.

First, you will learn how to form gerundives, then how to use them.  Second, you will learn how to form the gerund, then how to use it.

Forming Gerundives

The gerundive (which is also called the future passive participle) is a verbal adjective formed by adding -ndus, -a, -um to the present stem of a verb.  It declines like a first and second declension adjective. E.g. amandus, habendus, ducendus, capiendus, audiendus. Here are the complete forms for amo, amare, amavi, amatum.

For 3rd -io conjugation and 4th conjugation verbs add iendus, -a, -um.  Here are the complete forms for capio, capere, cepi, captum.

Note that gerundives can also be made from deponent verbs that are transitive (they take objects) or impersonal verbs.  Unlike the other forms of deponent verbs, gerundives from deponent verbs have passive meanings and should be translated passively. Examples are given in the following sections.

Uses of the Gerundive: Passive Periphrastic

The most common usage of the gerundive is called the Passive Periphrastic.  In this construction, the gerundive appears with a form of the verb sum to denote necessity or obligation. The gerundive will agree (case, number, and gender) with the subject of the sentence, so it will normally be in the nominative case. 

Carthago delenda est.
Carthage should be destroyed (literally: “Carthage is to be destroyed.”)

Hoc non patiendum est.
This must not be endured (literally: “This is not to be endured.”)

If, however, the passive periphrastic is used in an indirect statement, the gerundive will be in the accusative to agree with the accusative subject.

Rex dixit patriam servatam esse.
The king said that the fatherland should be saved.  

As with many passive verbs, a noun may be used to express the agent of the action.  With regular passive verbs, an ablative of agent would be used, however, in this new construction, the agent is expressed with a dative of agent.  This is a noun or pronoun in the dative case without any preposition.  The dative of agent is translated as “by . . . “

Omnibus in arenā sumus videndae.
We must be seen by everyone in the arena. (literally: “We are to be seen by all in the arena.”)

Sequendi sunt hostes mihi.
I must pursue the enemies. (literally: “The enemies must be pursued by me.”)

N.B. Sometimes the dative of agent is employed with the perfect passive verbs, particularly in poetry.

Uses of the Gerundive: Purpose

The gerundive can also be used to express purpose. There are two ways to do this:

Ad + Accusative Noun + Gerundive 

The preposition ad regularly takes an accusative noun and shows motion toward something (e.g. ad forum = “to the forum”).  When ad is used with a noun that is modified by a gerundive, it indicates purpose.  It is best to translate ad as “to” or “in order to,” then the gerundive with the modified noun as its object.  For example:

Ad libros legendos venit Aelia.
Aelia is coming to read books. (literally: “for the purpose of books to be read.”)

Perpetua se somno tradit ad visionem accipiendam.
Perpetua goes to sleep to receive a vision. (literally: “for the purpose of a vision to be received.”)

Genitive Noun + Gerundive + Causā or Gratiā

You learned in Unit 3 Verba that causā in the ablative case preceded by a genitive noun is translated “for the sake of _____,” however, when that noun is modified by a gerundive, it indicates purpose.  This is also true for gratiā with a preceding genitive.  It is best to translate causā or gratiā as “to” or “in order to,” then the gerundive with the modified noun as the object.  For example:

Librorum legendorum gratiā venit Aelia.
Aelia is coming to read books. (literally: “for the sake of books to be read.”)

Perpetua se somno tradit visionis accipiendae causā.
Perpetua goes to sleep to receive a vision. (literally: “for the sake of a vision to be seen.”)

Uses of the Gerundive: Simple Participle

The gerundive can also be used as a simple future passive participle (still denoting a sense of obligation), though this is not a common construction.

Fortis et laudanda puella in arenā est.
The girl in the arena is strong and praiseworthy (lit. “to be praised”)

Crimen non ferendum a rege factum est.
An unbearable crime has been committed by the king (lit. “a crime not to be born”)

Forming Gerunds

The gerund is the neuter singular form of the gerundive used as a noun.  Remember that a gerundIVE is an adjectIVE, but a gerund is a noun. The gerund is translated actively and does not exist in the nominative case. If the sentence calls for a verbal noun in the nominative case, the infinitive is used.

In English, we use gerunds often to express a verbal idea as a noun, e.g. “I enjoy running.”   In English we use “-ing” to form gerunds, which is also the form for Present Active Participles.  This can be confusing until it is clear that gerunds are nouns and participles are adjectives.  Compare these examples below:

Aelia cognoscit gaudium legendi. (gerund)
Aelia understands the joy of reading. 

Aelia, legens librum, studet philosophiae. (participle)
Aelia, reading a book, studies philosophy.

Here are some further examples of the gerund, in all four cases in which it can appear:

Aelia sequitur artem scrībendī. (Genitive)
Aelia pursues the art of writing.

Perpetua dat tempus precando. (Dative)
Perpetua gives time to writing. 

Christiani gaudent inter caedendum.  (Accusative)
The Christians rejoice during the killing.

Legendo discunt pueri puellaeque.  (Ablative)
The boys and girls learn by reading.

Uses of the Gerund: Purpose

Just like the gerundive above, the gerund can also be used to express purpose.  There are two ways to do this:

Ad + Accusative Gerund
The preposition ad regularly takes an accusative noun and shows motion toward something (e.g. ad forum = “to the forum”).  However, when ad is used with a gerund, it indicates purpose.  In this construction, it is best to translate ad as “to” or “in order to.”  For example:

Ad legendum venit Aelia.
Aelia comes to read.

Perpetua arenam intrat ad moriendum. (arena, -ae f. - arena)
Perpetua enters the arena to die.  

Genitive Gerund + Causā or Gratiā

Causā (in the ablative case) preceded by a genitive noun is translated “for the sake of _____,” however, when that noun is a gerund, it indicates purpose.  This is also true for gratiā with a preceding genitive.  It is best to translate causā or gratiā as “to” or “in order to,” for example:

Hilarianus loquendī causā surgit.
Hilarianus rises in order to speak (lit. “for the sake of speaking”)

Perpetua audiendi gratiā propius movet.
Perpetua moves closer in order to hear (lit. “for the sake of hearing”)

Gerunds vs. Gerundives

The gerund can be used with a direct object, however, this is uncommon.  Instead, the gerundive is preferred in this situation.  For example, in the following sentence, a gerund could be used in Latin:

Aelia venit ad legendum libros.
Aelia comes to read the books.

However, the Romans preferred to use a gerundive in this type of sentence.  Libros would be the object of ad and the gerundive would modify libros.

Aelia venit ad libros legendos.
Aelia comes to read the books.

Supines: Forms and Uses

The Supine is a verbal noun of the fourth declension. It has only two forms: the accusative singular (-um, the same form as the fourth principal part), and the ablative singular (-ū, formed by adding -ū to the fourth principal part stem). Each form has a specific way it is used: 

Accusative Supine + Verbs of Motion

The accusative supine is used after verbs of motion to express purpose. You translate it as “to ____.”

Aelia vēnit iuratum.
Aelia came to take an oath.

Pater sorores ad Perpetuam misit rogatum iterum.
The father sent her sisters to Perpetua to ask again. 

Ablative Supine + Certain Adjectives and Nouns

The ablative supine is used with select adjectives and nouns (e.g. mīrābile, facilis, dignum, fas, nefas, and opus) to express an ablative of respect or specification.  That is, the supine clarifies the way in which something is true. You translate it as “to _____”:

mīrābile dictū
wonderful to tell  

facilis factū
easy to do

Si fas est dictū.
If this is right to say.

Relative Clause of Purpose (Review)

As you learned in Unit 7, purpose clauses typically begin with ut or ne and are followed by a subjunctive.  However, purpose can also be expressed using a relative clause with a subjunctive.  You may translate them as ut/ne purpose clauses or as a relative clause.

Perpetua, quae pudorem contineret, femorem texit.
Perpetua, who would maintain her modesty, covered her thigh.
Perpetua covered her thigh in order to maintain her modesty.

Relative Clause of Characteristic

When describing the type of person or thing, or a general characteristic of someone, Latin uses a relative clause with a subjunctive verb.  In English, this type of clause can be translated using “the kind of” or “the sort who/which.”

Perpetua, quae nihil timeat, arenam intrat.
Perpetua, the sort of woman who fears nothing, enters the arena.
Perpetua, the kind of woman who fears nothing, enters the arena.

Relative Clause in Indirect Statement

When a relative clause occurs within an indirect statement, the verb will either be subjunctive or indicative.  The verb of the relative clause will usually be subjunctive, as are most subordinate clauses in indirect statements.  However, if the relative clause is stating a fact that is true independent of the indirect statement and is information given by the author, not the speaker, the verb will be indicative.  

Custos dixit nos duci ad carcerem, in quem amici teneantur. (subjunctive)
The guard said that we are being led to the prison, in which my friends are held.

Custos dixit nos duci ad carcerem, qui in urbe est. (indicative)
The guard said that we are being led to the prison, which is in the city.