The Hungarian historians used the Képes Krónika 30 solely when they interpreted the events of 1071. The Képes Krónika recorded only the Hungarian party’s opinion. According to the Hungarian scholars, the Hungarian–Byzantine relationship was variable at that time and the invasion of the Pechenegs was a Byzantine aggression. Many outstanding scholars of the field stated, that the attacking Pechenegs were Byzantine mercenaries. Another argument of the Hungarian historians was that the frontier guard Pechenegs were in confrontation with the Byzantine government. The above mentioned reconstruction is problematic in many ways, therefore a new approach is needed. The present article points out, that the Hungarian–Byzantine relationship was very good from St. Stephen’s time (997–1038) till the 1060s. In order to gain a better understanding of the whole situation, additional sources have to be drawn into the research. The Byzantine government did not want a multifront war. It is a fact, that the emperor (Rómanos Doigenes IV [1068–1071]) was an experienced soldier and in early 1071 he prepared against the Seljuks at the Eastern part of the empire. Thus his aim was to preserve peaceful relations with the other neighbours of the Byzantine Empire. It is pointed out in this article, that the frontier guard Pechenegs revolted only in 1074, because they did not receive their pay. The Byzantine Empire had a good information system. Therefore the frontier guard Pechenegs always followed the commands before 1074. Meanwhile, according to the PVL (Historical text tradition of the Kievan Rus.) in 1071 the Cumans crossed the Dnieper river and attacked the border forts of the Kievan Rus. Pletneva argues that the main direction of the Cuman attack was the southern Bug river. My reconstruction is the following: the Pechenegs who had been living between the Dnieper and the Lower Danube rivers, escaped when the Cumans attacked them. They crossed the Lower Danube with the help of the frontier guard Pechenegs. For this reason, plundering of the border province was not an option for them. So the fleeing Pechenegs attacked the territory of the Kingdom of Hungary to plunder it. The Hungarian chiefs did not believe the Byzantine government and accused them for the incident. In retaliation, the Hungarians conquered Byzantine territories between the Drava and the Sava rivers and successfully besieged Nándorfehérvár/ Belgrade.