In the view of medieval Christians, the Roman Empire was indivisible and its emperor held a somewhat hegemonic position even over Christians who did not live within the formal borders of the empire. The term is mostly used in regards to medieval Europe and is often used in particular for the long-lasting dispute between the Byzantine emperors in Constantinople and the Holy Roman emperors in modern-day Germany and Austria as to which emperor represented the legitimate Roman emperor. The problem of two emperors or two-emperors-problem (deriving from the German term Zweikaiserproblem) is the historiographical term for 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 two (or sometimes more) individuals who claimed the position simultaneously. Borders follow the political situation in 1190 AD. The problem of two emperors mostly concerns the medieval dispute between the rulers of the Holy Roman Empire (yellow) and the Byzantine Empire (purple) as to which ruler was the legitimate Roman emperor.