It sounds as though he remembers the first time that I met him, which places him well before...much of anything. I was on my way to Insomnia when we encountered each other, and the capital's fall was only the start--it was from there that he started traveling Lucis gaining the power of the gods and his ancestors.

In short, he knows absolutely nothing. He doesn't even know I'm anything more than the Imperial Chancellor, much less anything I did to him. No doubt he'll remember my real name at some point as well--I told him as much back in Niflheim.