This study, conducted according to the micro-storia paradigm, is based on the exhaustive analysis of an important unpublished private archive collection. Except for one of the brothers of the first ironmaster, a precursor of Lavoisier, the Rey family has, never to date, been the subject of any publication. The first notable figure of the Reys was a trader in Le Bugue (Périgord) in 1590, a dedicated Reformist. Among his six children, we will focus on one of his sons, born circa 1570, who bought a forge in 1601, Forge Neuve de La Borie, located in what can be called the “industrial valley” of the Manaurie river, an affluent of the Vézère river. He is thus a contemporary of the two events which were going to drastically alter the future of Western Europe: pre-industrialization and the Reform When he died in 1630, his son followed in his footsteps and ran his trade, while getting closer to nobility by means of his marrying Esther de Vins de La Fleunye. This upward mobility was brutally stopped by the abduction of his elder daughter by a very young member of the Saint-Éxupéry family. The forge will be sold outside the family in 1757. The archival collection can boast of four Record Books (Books of Reason) which offer precious information about the forge and its workers. Consequently, the religious, economic, and social axes will guide the dynamics of our work.