§150. Case-Forms of quī and quis

The Relative, Interrogative, and Indefinite Pronouns are originally of the same stem, and most of the forms are the same (compare § 147 with § 148). The stem has two forms in the masculine and neuter, quo-, qui-, and one for the feminine, quā-. The interrogative sense is doubtless the original one.

a. Old forms for the genitive and dative singular are quôius, quoi.

b. The form quī is used for the ablative of both numbers and all genders; but especially as an adverb (how, by which way, in any way), and in the combination quīcum, with whom, as an interrogative or an indefinite relative.

c. A nominative plural quēs (stem qui-) occurs in early Latin. A dative and ablative plural quīs (stem quo-) is found even in classic Latin.

d. The preposition cum is joined enclitically to all forms of the ablative, as with the personal pronouns (§ 143. f): as, quōcum, quīcum, quibuscum.