John I Tzimiskes
Chroniclers John Skylitzes and George Kedrenos wrote that in 971, during battles between Romans (Byzantines) and Rus' people led by Sveinald (Sviatoslav I), the dwellers of the north side of Danube came to Emperor John I Tzimiskes and they handed over their fortresses and the Emperor sent troops to guard the fortresses. During those times, Northern part of Danube were dwelled by sedentary Vlachs and tribes of nomad Pechenegs who lived in tents.