Wasnt Naples and Sicily considered a Papal fief by that time? I am sure that an invasion to these territories would lead to a permanent fall out between HRE and Papacy... And with a strong Pope in Rome he could have the Imperial Title revoked and given to someone else causing severe chaos in Europe thus opening the way for Ottomans to continue their expansion to Central Europe...
If they had a valid claim on these kingdoms, then the papacy would have been in a lot weaker position to oppose an invasion as long as the emperor would have respected the fact that he holds these kingdoms as Papal fiefs.
This doesn't mean that the pope will be happy with this situation, so the Papacy in all likelihood will try to restore independency for these kingdoms. Restoring these kingdoms to independency can be done peacefully, by allowing a younger son of the emperor to inherit these kingdoms; or by destabilizing the empire and promising these kingdoms to any christian prince/noble, who conquers them. However it doesn't mean that this will work; it may very well be possible that the Papacy will have to accept the new situation.
Being a vassal of the Pope would be an unacceptable position for the Emperor.
That would mean to admit defeat on the whole Middle Age power struggle
Being a vassal of the Pope would be an unacceptable position for the Emperor.
That would mean to admit defeat on the whole Middle Age power struggle
OTL Charles V and Charles VI were as king of Naples nominally a vassal of the pope for that title, but they also controlled lots of land as truly independent monarchs (although de facto they were just as powerful in Naples).
Furthermore quite some European Christian kingdoms were at one point papal fiefs, IIRC some of the Iberian kingdoms started out this way (at least IIRC Portugal did) and John Lackland, king of England, had to accept the pope as his feudal overlord.
Uhm
I think you are mistaking the position of a king with that of the emperor.
It is perfectly right for a king to be vassal of the pope, since most catholic kings recognize a spiritual preminence to him.
The holy roman emperor, on the other hand is in a position much more like the ancient Byzantine one: in principle he claims preminence both in wordly and in spiritual matters, i.e. he is both wordly ruler and head of the church.
That's Emperor Orbis Terrarum, imago Christi
(and that's the reason for them having that small orb surmonuted by a cross)
That's all the Middle-age Investiture War was about.
From when Charlemagne was invested by the pope, the popes claim to be higher than the emperors (since they crown them), while the emperors deny that, since their nominal source of power (roman) precede that of the pope.
I did not know the fact that ChV and VI tried that but I assume that it was because they were deeply catholics (IIIRC ChV renounced to the throne and ended as a monk) and at that time the Papacy had already won his contest
The status of papal fief was attached to these kingdoms, and as such the emperor would only be a nominal vassal for these kingdoms (this position would have been recognized, but only when necessary)*, but not in the empire or his other possessions. Or more technically the emperor in his role of king of Naples would accept the pope as his overlord, but as emperor he would claim the position you described.