Son du Martel explores the inexplorable: the life of a king who reigned in the darkest, perhaps, centuries considered "obscure" of the Middle Ages, whose collective memory only retains the name, "fun", and scholarly history some early mummified fragments; It is not, moreover, a question of this object considered as a whole, but of its first section exclusively, of all the least exposed to the mnemogenic eyes of the outside, the one whose confines are fixed, more or less, by the family circle. A formidable challenge, therefore, which requires to exchange the focal point of the macroscopic historian, for an instrument capable of penetrating the depths. The birth of Pepin is evoked through the life of Fr. Ermin de Lobbes. His name and that of his father, characteristics of the dynasty, lead to a radical rethinking of the origins. Those of her mother are also scrutinized and her kinship enriched with "new" members. The education of the young prince is approached from two angles: that of the context, thanks, essentially, to sources from Saint-Denis, and that of the "program", an excuse to examine at fresh expense the delicate question of the illiteracy of the first Carolingians. Finally, the "adoption" by Liutprand, king of the Lombards, gives rise to an investigation of the text, a short chapter of the Historia Langobardorum of Paul Deacon, and to another, in parallel, on the rites and ceremonies that punctuate male growth, beard and hair. Brepols.