Abstergo Entertainment

A card, spell, or permanent is historic if it has the legendary supertype, the artifact card type, or the Saga subtype. Having two of those qualities doesn’t make an object more historic than another or provide an additional bonus—an object either is historic or it isn’t.

You don’t have to choose a target historic card to activate Abstergo Entertainment’s last ability. However, if you do, and that card is an illegal target at the time the ability tries to resolve, it won’t resolve and none of its effects will happen. No graveyards will be exiled.

An ability that triggers “whenever you cast a historic spell” doesn’t trigger if a historic card is put onto the battlefield without being cast.