The subject agreement inflection of the Breton verb distinguishes six person-number forms and a seventh impersonal form. The impersonal has the generic and arbitrary uses of the class best studied for Germanic man, French on, and Romance se/si, as well as its Irish cognate.We take up two remarkable aspects of the Breton impersonal. One is recent dialectal extensions of the impersonal morphology to prepositional and nominal inflections, completing the otherwise thoroughgoing parallelism of these three systems characteristic of Breton and related languages.In the theory of impersonals, the extensions have the potential to shed light on the limitation of this class of impersonals to subjects. Our second focus is the phi-features of the impersonal in anaphoric dependencies. Breton bolsters the generalisation that this class of impersonals is deficient in phi-features and thereby unable to antecede personal pronouns. However, recent dialectal developments have resulted in grammars where different personal pronouns have become impersonals, and their convergence has created systems where the impersonal antecedes a remarkably wide but still limited range of pronouns. Our study aims to cover the rich but partial descriptions of these phenomena over the Modern Breton period, bolstered by corpus examples, and to extend it by a pilot study of current native speaker competence.< Leer menos