English summary: Little is known today about Maecenas, a descendant of Etruscan kings, friend of the first Emperor, Augustus, and key figure in the final years of the Roman Republic and the emerging Empire.As a diplomat, an advisor to Octavian and Augustus and even, briefly, head of the government of Rome and Italy, he played a major role in the emergence of what was essentially a monarchic regime. This political commitment caused him to be viewed by his senator adversaries (and later by Seneca) as an unsavoury person. His adherence to Epicureanism, in particular, was exploited in order to discredit a knight who should never have had to take on the responsibilities thrust upon him within the Roman State. Nonetheless, it is primarily as a protector of the poets - Virgil, Horace and Propertius in particular - that Maecenas left his name to posterity and very soon came to symbolise the Golden Age of literary patronage.It was under his patronage that some of the leading works of Latin literature were written, most notably the Aeneid. He, among others, spearheaded a cultural policy aimed at giving Rome a literature capable of rivalling with that of the Greek world. This singular figure with his taste for both obscurity and for provocation, was prominent in an Epicurean circle which may have been therapeutic for his anxious nature. Maecenas marked the history of Rome in exceptional ways.The product of five years of research, this biography revives the portrait of Maecenas, shedding light not only on his political activism, but also on his role as a protector of Latin literature, while conveying the singularities of an unconventional, controversial, and often misunderstood, figure. French description: Mecene, descendant des rois etrusques, ami du premier empereur, Auguste, et personnalite phare de la fin de la Republique romaine et de l'Empire naissant, demeure aujourd'hui encore une figure meconnue.Tout a la fois diplomate, conseiller d'Octavien/Auguste et meme, durant un temps, responsable du gouvernement de Rome et de l'Italie, il a joue un role majeur dans l'emergence d'un regime d'essence monarchique. Cet engagement politique lui a valu, de la part de ses adversaires senateurs (et, plus tard, de Seneque), un portrait noir. Son adhesion a l'epicurisme, notamment, fut instrumentalisee afin de decredibiliser un chevalier qui jamais n'aurait du revetir les responsabilites qui furent les siennes au sein de l'Etat romain. C'est toutefois essentiellement en tant que protecteur des poetes, Virgile, Horace et Properce en particulier, que Mecene a laisse son nom a la posterite. Tres vite, il a symbolise l'age d'or du patronage litteraire.Sous son egide, certaines des oeuvres majeures de la litterature latine ont vu le jour, l'Eneide en premier lieu. Il a ete l'un des fers de lance d'une politique culturelle visant a donner a Rome une litterature capable de rivaliser avec celle du monde grec. Personnalite singuliere ayant tout a la fois le gout de l'ombre et celui de la provocation, figure centrale d'un cercle epicurien qui servit sans doute en partie de therapie a sa nature inquiete, Mecene est une figure hors norme de l'histoire de Rome.Resultat de cinq annees de recherche, cette biographie renouvelle le portrait de Mecene, eclairant tout a la fois son action politique, son oeuvre de protecteur des lettres latines et les singularites d'un personnage peu orthodoxe, controverse et souvent incompris.Philippe Le Doze est agrege, maitre de conferences en histoire ancienne a l'universite de Reims Champagne-Ardenne et membre du Centre d'Etudes et de Recherche en Histoire culturelle (CERHiCEA 2616). Il a publie Le Parnasse face a l'Olympe. Poesie et culture politique a l'epoque d'Octavien/Auguste (2014).