Many monuments of that period have been found around Madara, Shumen, Novi Pazar, the village of Han Krum in north-eastern Bulgaria, as well in the territory of modern Romania, where Romanian archaeologists called it the "Dridu culture".
Palju selle aja mälestisi leidub Madara, Šumeni, Novi Pazari, Han Krumi ümbruses Kirde-Bulgaarias, samuti tänapäeva Rumeenia territooriumil, kus rumeenia arheoloogid kutsuvad seda "Dridu kultuuriks".