Even more confusingly , Gregory does not give him any title while mentioning his death. The Liber Historiae Francorum refers to him initially as rex .
Even more confusingly , Gregory does not later twice calls him principem Romanorum ( the Roman emperor ) .
Even more confusingly , Gregory does not give him any title while mentioning his death. The Liber Historiae Francorum refers to him initially as rex , but later twice calls him principem Romanorum ( the Roman emperor ) .