Mureș, Criș, Tisza and Toutis as within its territory. Archaeologist rejects Kristó's theory, because no archaeological finds from the late 9th century evidence Moravian influence in Crișana. The Bulgarians also benefited from the fall of the Avar Khaganate. One of the military commanders of Omurtag of Bulgaria drowned in the Tisza, showing that Omurtag, who ruled between 814 and 831, attempted to expand his authority towards this river. The Bulgarians allied with the Franks and invaded Moravia in both 863 and 883. Based on sources from around 870, the Persian scholar Gardizi wrote of two peoples, the Nandarin and the Mirdāt, whose lands were ten days' journey apart. Historians István Bóna and György Györffy identify the Nandarins as Bulgarians (because nándor was the Hungarian exonym for the Bulgarians), and the Mirdāt as Moravians. If their identifications are valid, the distance between Bulgaria and Moravia was about circa 870. Anonymus's narration Menumorut and his duchy Menumorut ruled an area bordered by the rivers Tisza, Mureș, Someș, and the Igyfon Wood at the time of the Magyars' invasion, according to the Gesta Hungarorum. Anonymus also wrote that "the peoples that are called Kozár", identified by historians as Khazars, inhabited this realm, together with the Székelys. Menumorut's main fortress was located at Biharia, according to Anonymus. An early medieval fortress was found here, and some historians (including Sălăgean) have identified it as Menumorut's capital, although others (for instance, Florin Curta) argue that nothing proves that the fortress was built before the 10th century. Anonymus wrote that Menumorut was the grandson of one "Prince Marót" (whose name was derived from the ancient Hungarian exonym for the Moravians), who he states was ruler of Crișana in the times of Attila the Hun. According to the Gesta, Menumorut communicated "haughtily with a Bulgarian heart" with the Magyars' envoys, informing them that "the emperor of Constantinople" was his lord. The Gesta describes Menumorut as a polygamist, stating that he "had many concubines". Anonymus even suggested that Menumorut's name was connected to the Hungarian word for stallion (mén) because of his womanizing nature. According to historian Neagu Djuvara, Menumorut's name is a Hungarian form of a Turkic (possibly Bulgar) proper name, but he does not give a suggestion. The Hungarian conquest The Magyars entered the Carpathian Basin through the Northern Carpathians, according to the Gesta Hungarorum. After conquering the northeastern region, their leader, Grand Prince Árpád, sent two