It is demonstrated that contrary to the received opinion the Ancient Greek 1sg. optative in -οιμι (e.g. ἐθέλοιμι ‘wish’) and its (Old) Church Slavonic counterpart in -ěmь (e.g bǫděmь ‘be’), both reflecting a primary ending instead of the expected secondary ending are not innovations but reflect the original situation. Following a discussion of earlier accounts of these forms, it is argued on the basis of comparative evidence and earlier research concerning other domains of Indo-European verbal morphology (the subjunctive and indicative/injunctive) that in Proto-Indo-European, verbs originally had a paradigm with primary endings and with secondary endings that were distributed complementarily depending on information/discourse status: forms with primary endings denoted information newly introduced into discourse, while forms with secondary endings denoted information already given/accessible in discourse. The optatives in -οιμι and -ěmь retain the primary ending, because verb-forms expressing new information were pragmatically favoured in the first person of the optative.