A marker at the Palmyrene's southwestern border was found in 1936 by Daniel Schlumberger at Qasr al-Hayr al-Gharbi, dating from the reign of Hadrian or one of his successors, which marked the boundary between Palmyrene and Emesene (Pliny the Elder asserted that both territories were contiguous); this boundary probably ran northwards to Khirbet al-Bilaas on Jabal al-Bilas where another marker, laid by Roman governor Silanus, has been found, 75 kilometers northwest of Palmyra, probably marking a boundary with the territory of Epiphania.