They, their, them.—When hit had been changed into it, when heó had been replaced by she, and when the single form the, as an article, had come to serve for all the cases of all the genders, two circumstances took place: 1. The forms þám and þára as definite articles became superfluous; and, 2. The connexion between the plural forms hí, heom, heora, and the singular forms he and it, grew indistinct. These were conditions favourable to the use of the forms they, them, and their, instead of hí, heom, heora.
Theirs.—In the same predicament with hers and its; either the case of an adjective, or a case formed from a case.
Than or then, and there.—Although now adverbs, they were once demonstrative pronouns, in a certain case and in a certain gender.—Than and then masculine accusative and singular, there feminine dative and singular.
An exhibition of the Anglo-Saxon declension is the best explanation of the English. Be it observed, that the cases marked in italics are found in the present language.
I.
Se, seó.
Of this word we meet two forms only, both of the singular number, and both in the nominative case; viz. masc. se; fem. seó (the). The neuter gender and the other cases of the article were taken from the pronoun þæt (that).
II.
þæt (that, the), and þis (this).