"I mean all of English magic," Strange repeats, a bit annoyed. And for all of Strange's 'let's try not to explain it in a way that raises too many questions' that he thought just mere seconds earlier, he's going to have to explain this in a way that raises too many questions. What does that even mean, well it means all of English magic, well who was used as the vessel in the first place, it was supposed to be the Raven King, you summoned the Raven King, et cetera et cetera.

"Norrell and I summoned the Raven King, he left, we wanted to call him back so we used symbolic magic, offering up Norrell's library as a token to represent all of English magic. It...went oddly, but everything wound up right in the end."

Except for the whole being cursed thing.