Your inability to comprehend what is posted is getting annoying. If you read the entire text a few more times, perhaps you'll see that "the rest of Christendom" necessarily includes the Protestant denominations.
Again, the ultimate source of deception is Satan himself. Moreover, as eager as most Catholics are to point out that it was the Catholic church from which all other denominations sprouted, it seems a bit ironic that you feel this need to eliminate the Catholic church completely when it comes to such blatant chronological facts.