Pokémon Omega Ruby and Pokémon Alpha Sapphire announced

As a nod to your trainer in X or Y being given a Kanto starter to run the same task? Yeah.

But if you're talking about the actual first mega evolution, it's heavily implied (if not directly stated) that a Lucario led to the first mega evolution.

I meant for trainers learning of it, not learning how the very first did it. So, the first one you said.