224. RULE.  Agreement of the Relative. A relative pronoun must agree with its antecedent in gender and number; but its case is determined by the way it is used in its own clause.

225. Interrogative Pronouns.  An interrogative pronoun is a pronoun that asks a question.  In English the interrogatives are who? which? what? In Latin they are quis?\ quid?\ (pronoun) and qui:?\ quae?\ quod?\ (adjective).

226. Examine the sentences

  a. Who is the man? Quis est vir?
  b. What man is leading them? Qui vir eos ducit?

In a, who is an interrogative pronoun.  In b, what is an interrogative adjective.  Observe that in Latin quis\, quid\ is the pronoun and qui:\, quae\, quod\ is the _adjective_.

227. 1.  The interrogative adjective qui:\, quae\, quod\ is declined just like the relative pronoun. (See Sec. 221.)

2.  The interrogative pronoun quis\, quid\ is declined like qui:\,
quae\, quod\ in the plural.  In the singular it is declined as
follows: 

MASC.  AND FEM.  NEUT. 
Nom. quis, who? quid, what? which?
Gen. cuius, whose? cuius, whose?
Dat. cui, to or for whom? cui, to or for
what or which?
Acc. quem, whom? quid, what? which?
Abl. quo:, from, etc., whom? quo:, from, etc.,
which or what?

NOTE.  Observe that the masculine and feminine are alike and that all the forms are like the corresponding forms of the relative, excepting quis and quid.

228. EXERCISES

I. 1.  Quis est aeger?  Servus quem amo est aeger. 2.  Cuius scutum habes?  Scutum habeo quod legatus ad castellum misit. 3.  Cui legatus suum scutum dabit?  Filio meo scutum dabit. 4.  Ubi Germani antiqui vivebant?  In terra quae est proxima Rheno Germani vivebant. 5.  Quibuscum[1] Germani bellum gerebant?  Cum Romanis, qui eos superare studebant, Germani bellum gerebant. 6.  Qui viri castra ponunt?  Ii sunt viri quorum armis Germani victi sunt. 7.  Quibus telis copiae nostrae eguerunt?  Gladiis et telis nostrae copiae eguerunt. 8.  A quibus porta sinistra tenebatur?  A sociis porta sinistra tenebatur. 9.  Quae provinciae a Romanis occupatae sunt?  Multae provinciae a Romanis occupatae sunt. 10.  Quibus viris dei favebunt?  Bonis viris dei favebunt.

    [Footnote 1:  cum\ is added to the ablative of relative,
    interrogative, and personal pronouns instead of being placed
    before them.]

  [Illustration:  GERMANI ANTIQUI]

II. 1.  What victory will you announce? 2.  I will announce to the people the victory which the sailors have won. 3.  The men who were pitching camp were eager for battle. 4.  Nevertheless they were soon conquered by the troops which Sextus had sent. 5.  They could not resist our forces, but fled from that place without delay.