WI: Emperor Leo IV lives longer

[GauchoBadger]

Leo IV, The Khazar, was a byzantine emperor with good relations to the roman papacy. However, his untimely death led to the ascension of his wife Irene to the throne.
Pope Leo III refused to acknowlege a woman as the despot of Rome and decided to crown Charlemagne as roman emperor instead, creating the first instance of the Holy Roman Empire. It is reported that Charles himself was a bit reluctant to accept the title at first.
So, what if Leo IV had not died so early, managing to further strengthen his relations with the roman papacy?
Could the HRE have been butterflied away and remained as just the Frankish Empire?
Or were there more factors at play?

 

[Romanos_the_Fourth]

I doubt that the Pope would prefer having an Iconoclast on the Byzantine throne, though. Leo would have to completely obliterate his father's policies regarding Icons if he were to achieve any lasting pact with Rome.

Here's an idea. Leo restores the Iconodules to power, then betroths his son Constantine to Rotrude, daughter of Charlemagne (there was talk of this historically).