The progenitor, "sevastokrator" Dejan, was a magnate in the service of Emperor Dušan, and also the Emperor's brother-in-law through his marriage with Teodora-Evdokija. Dejan held the "župe" (counties) of Žegligovo and Preševo under Dušan, and later received the title of "despot" during the rule of Dušan's son, Emperor Uroš V, when he was appointed the administration Upper Struma with Velbužd, after the death of powerful "despot" Jovan Oliver. After Dejan's death between 1358 and 1365, most of his province was given to Vlatko Paskačić, besides the initial counties of Žegligovo and Preševo, which were left to his two sons, Jovan and Konstantin. The brothers, who ruled jointly, managed to double the extent of their province during the Fall of the Serbian Empire following Emperor Uroš V's death, chiefly to the south; the lands now covered from Vranje and Preševo to Radomir, in the south to Štip, Radovište and Strumica. In 1373, two years after the devastating Battle of Maritsa, the brothers became vassals to the Ottoman Empire. After the death of Jovan in 1377, Konstantin continued to rule under Ottoman overlordship. Konstantin and his provincial neighbour and fellow Ottoman vassal, Prince Marko, fell at the Battle of Rovine in 1395.