All prophecy is a done deal for a very long time now.
The biblical prophesied apostasy was the Roman assembly. Consider the word "vatican" (Latin mons vaticanus). "Vatic" means "of or pertaining to prophecy. Oracular."
http://www.merriam-webster.com/dictionary/vatic
And "mons" refers to a hill or small mountain as in Vatican Hill.
Now for the prophecy:
Isa 14:12 ¶ How art thou fallen from heaven, O Lucifer, son of the morning! how art thou cut down to the ground, which didst weaken the nations!
Isa 14:13 For thou hast said in thine heart, I will ascend into heaven, I will exalt my throne above the stars of God: I will sit also upon the mount of the congregation, in the sides of the north:
Isa 14:14 I will ascend above the heights of the clouds; I will be like the most High
Rome is to the "sides of the north" in relation to Israel - north and west