I am curious to know if anyone is aware of an online location in which the entirety of Pope St. Leo's sermons may be found (translated into English). The matter is of great interest to me, so any assistance would be appreciated. One of the most fascinating compositions is that of sermon #4. This particular number is (not surprisingly) omitted from the collection on New Advent (which I once believed to possess a comprehensive collection). In short, it destroys heterodox notions concerning the "keys of the kingdom of heaven". Behold an excerpt! :
"Et quaecumque ligaueris super terram, erunt ligata et in caelis, et quaecumque solueris super terram, erunt soluta et in caelis.
Transiuit quidem etiam in alios apostolos ius istius potestatis, et ad omnes ecclesiae principes decreti huius constitutio commeauit, sed non frustra uni commendatur, quod omnibus intimetur.
Petro enim ideo hoc singulariter creditur, quia cunctis ecclesiae rectoribus Petri forma proponitur. Manet ergo Petri priuilegium, ubicumque ex ipsius fertur aequitate iudicium."
“Whatsoever you shall bind on earth, it shall have been bound in heaven, and whatsoever you shall loose, shall have been loosed in heaven”:
"He passed over the other apostles, the right of this power, the princes of the decree and to all the churches of this common statement of the case, but not recommended in vain to one, which is to all be communicated.
This power is confided to him in a special manner, because the type of Peter is proposed to all the pastors of the Church. Therefore the privilege of Peter dwells wherever judgment is given with his equity".
I don't know which Pope Leo you speak of. I do know that Pope Leo XIII had a vision that the antichrist would sit on the throne of Peter. Catholics believe in the appearance of "Our Lady of La Salette" who also made the same prophesy. These occurred in relatively recent times, the nineteenth century if I am not mistaken.