Learn Latin from the Romans A Complete Introductory Course Using Textbooks from the Roman Empire

In the nominative this pronoun is not used nearly as often as its English equivalents, because the relevant information is normally conveyed in the verb endings. In the genitive eius and eōrum/eārum are used for possession freely; there is no possessive adjective for this pronoun as there are for the personal and reflexive pronouns. The genitives eius and eōrum, of course, do not agree with the nouns possessed: it is purely coincidental that one happens to end in -us and the other in -um. Thus māter eius means ‘his/her/its mother’, māter eōrum ‘their (masculine possessors) mother’, and māter eārum ‘their (feminine possessors) mother’.