I can see it now.
Silence falls across Europe, broken only by the soft smoldering of burning towns and the occasional vulture's cry. Pillars of smoke climb into the heavens, but none are left to say which God is there to receive this vast, awful burnt offering.
Except these. First one footfall, then another sounds in the air. Ashes crunch under a slippered foot. A white-robed figure emerges from the smoke: the Pope, landless and bereft of all but the tiniest core of his court, he soldiers grimly on. He meets another, face and expression both dark. Together, the Pope and his Coptic rival walk on, meeting the Ecumenical Patriarch and the Patriarch of the East. A small band of mercenaries tries to accost them, but they are protected by the silent forms of holy warriors who melt from the shadows to protect the group. At last they reach the single castle left intact, and the soldier break open the doors. The gathered religious leaders enter, arraying themselves before the indolent figure that sits upon the throne.
"You think to stop me?" he laughs. "You, who couldn't even bring your God to protect His people?"
"Who knows?" replies the Ecumenical Patriarch. "Maybe He sent us?"
The religious leaders close in, various heavy religious icons clutched in their hands. The Pope bends down. Smiles.
"Maybe now you'll switch to Papal Investiture?"