In historiography, the problem of two emperors or two-emperor problem is the historical contradiction between the idea of the universal empire, that there was only ever one true emperor at any one given time, and the truth that there were often multiple individuals who claimed the position simultaneously. The term is primarily used in regards to medieval European history and often refers to in particular the long-lasting dispute between the Byzantine emperors in Constantinople and the Holy Roman emperors in modern-day Germany and Austria as to which monarch represented the legitimate Roman emperor.