What type of pronoun is used in the following Snetence Under the most splendid house in the city is still to be found the cellar where they store their roots as of old?

The pronouns in the sentence are:

• they, personal pronoun, third person, plural, subjective.
• their, possessive adjective, third person, plural, describes the noun 'roots'

Note: The Word 'where' is a relative adverb which introduces the adverbial clause 'where they store their roots as of old'.