Pour citer cet article Caroline SIMONET, « Les sceaux des sires et dames de Rozoy : le devenir des roses de Thiérache. Première partie : les origines », Revue française d'héraldique et de sigillographie-Études en ligne, 2018-5, décembre 2018, 31 p. The seals of the lords and ladies of Rozoy : the future of the three heraldic roses of Thiérache. First part : origins Rozoy is a small fiefdom located in Thiérache, in the North of France. Their lords, a modest noble lineage, managed to extend their domains and authority thanks to strategic marriages, inheritances and land purchases during the Twelfth and first part of the Thirteenth Century. They succeeded in having a son elected as bishop of Laon, one of the most important see of the kingdom, located not far away from Rozoy. The Rozoy are well-known concerning heraldry and sigillography thanks to the great equestrian seal of Alix, wife of Roger II de Rozoy : the lady is surrounded by the three heraldic roses of the lineage. This successful image tends to outshine the other seals owned by this family and the way the three roses were represented on them. This first article is dedicated to the emergence of seals and coats of arms in the Rozoy family in 1180-1210. Renaud, first Lord of Rozoy having a seal, didn’t use any coat of arms. However, his wife Julienne de Rumigny and his son Roger Irst had roses engraved on their great seals from 1195 on. Julienne used the same matrix for 13 years at least : the dowager’s figure is flanked by two roses. But the legend was reengraved, a new land replacing Rozoy in 1208. Did Julienne already owned her seal when she was still married to Renaud or was it engraved in 1195, at the same moment of her son’s first matrix ? Roger owned not one, as we thought till now, but two successive equestrian great seals and a small seal used as a counter-seal, all ornamented with the Rozoy coat of arms. There is no imprint of the seal of Roger’s wife, so we can’t maintain she used the three roses. A future article will analyse the next generation’s seals.