La suprematie politique des elites civiques aux epoques hellenistique et imperiale n''est plus a demontrer. Les moyens par lesquels certaines familles parvenaient a asseoir durablement leur preeminence dans le cadre specifique des poleis grecques, majoritairement democratiques, restent cependant insuffisamment analyses et la place de freres dans les processus de reproduction des elites n''a jamais fait l''objet d''une etude d''ensemble. Les strategies juridiques, economiques et sociales employees pour preserver et perpetuer le capital materiel et symbolique de l''oikos revelent en effet l''importance des solidarites entre freres ou entre freres et soeurs et la necessaire repartition des roles dans les fratries. En convoquant les archives epigraphiques des cites de plusieurs regions du monde grec (Grece, Macedoine, Egee, Asie Mineure) et en examinant de nombreuses sources litteraires (orateurs attiques, Menandre, Plutarque, litterature astrologique) et archeologiques (epigrammes funeraires, monuments familiaux), cet ouvrage se veut une contribution a l''histoire sociale des elites civiques au miroir des relations adelphiques. The political supremacy of civic elites in the Hellenistic and Imperial periods is a well established fact. However, the means by which certain families succeeded in establishing their pre-eminence over the long term within the specific framework of the Greek poleis, most of which were democratic, remain insufficiently analysed, and the role of brothers in the reproduction of elites has never been the subject of a comprehensive study. The legal, economic and social strategies employed to preserve and perpetuate the material and symbolic capital of the oikos reveal the importance of solidarity between brothers or between brothers and sisters and the necessary division of roles among siblings. By drawing on the "epigraphic archives" of cities in several regions of the Greek world (Greece, Macedonia, the Aegean, Asia Minor) and examining numerous literary (Attic orators, Menander, Plutarch, astrological literature) as well as archaeological sources (funerary epigrams, family monuments), this book aims to contribute to the social history of civic elites as seen through fraternal relations.