The purpose of this communication is to briefly discuss the role of a little-known military commander of Philip II’s army in the context of the Macedonian expansion in Thrace. Demetrius is mentioned as Philip’s admiral during the siege of Byzantium in 340 BC by Dionysius of Byzantium (Anaplus of the Bosporus 65). The lead sling bullets published here, bearing the name Demetrius and originating from the villages of Zhelad, Shumen district, the regions of Pavlikeni and Razgrad-Omurtag, as well as from Selymbria (modern Silivri), strongly confirm his participation in the campaigns of Philip II not only in the Propontis region, but also in the West Black sea coast and in Northeastern Thrace. Thus Demetrius would become the second Macedonian commander, together with the well-known Hipponikos, who are securely attested in a combination of historical, epigraphic and archaeological data. Future discoveries of sling bullets with Demetrius’ name could also serve as a reliable benchmark for identifying other historically unknown Macedonian commanders who took part in Philip II’s military campaigns.