The paper is dealing with the military role of late medieval manor houses (called in charters castellum, fortalitium, curia, or domus nobilitaria) during the wars against the Ottoman Empire. In the region under scrutiny (the Plain of the Temes River), there are  around 21 confirmed noble residences named castellum in medieval charters. At least five more such small fortifications were detected on the field but they are not mentioned in medieval documents. In the absence of systematic archaeological investigations, we were compelled to base our research upon medieval and premodern sources: charters and accounts, Christian and Ottoman chronicles, sketches. After the conquest of the territory in 1551-1552, the organization of ottoman nahijes mostly overtook the structure of medieval private and royal domains. The centers of these subunits were usually market towns, with a castle like a small stronghold nearby, used before as residences. Towards the middle of the 16^th century, the defensive role of the residences became more accentuated, for beginning with the 1390’s Ottoman raids started to represent a permanent menace for the inhabitants of the aforementioned region. However, sources reveal the fact that these small noble residences were suitable to ensure only temporary shelter against Ottoman raids or incursions and, in many cases, they were peacefully handed over. At the beginning, the Ottoman administration relied on the existing fortifications; later on, some were abandoned and new ones were constructed. It seems that, in the region we refer to, these strongholds have rather fulfilled the role of checkpoints, administrative centers or supply lines. At the end of our paper, we shall present three case studies of late medieval castles: Fellak/Felnac, Eperjes/ Chelmac and Facsád/Făget.