Reichsfürst
In 1410 Sigismund had been elected King of the Romans and was crowned Holy Roman Emperor in 1433. In 1436 he elevated the Counts of Cilli to the rank of Princes of the Holy Roman Empire (although they retained their title of "Graf" ()). The Habsburgs, whose strongest rivals they had become, reacted with a war that lasted until 1443, when an agreement of mutual inheritance was signed.