Which was, to lead him, in close secrecy, Even to Madeline's chamber, and there hide Him in a closet, of such privacy That he might see her beauty unespied, And win perhaps that night a peerless bride, While legion'd faires pac'd the coverlet, And pale enchantment held her sleepy-eyed. Never on such a night have lovers met, Since Merlin paid his Demon all the monstrous debt.
In today's edition of R. Kelly: Still Somehow Relevant, we learn that Porphyro's cunning plan apparently requires him to hide in Madeline's closet and look at her in private.
Suddenly Angela's freakout in stanza 16 starts making a lot more sense: Porphyro's arranging a private viewing of Madeline, peeping at her through the closet door.
Even though Angela and Porphyro both think the St. Agnes' Eve ritual is a dud, there's nevertheless a heightened supernatural air to the whole situation. Madeline isn't just going to be asleep, she's going to be under a spell of "pale enchantment," while fairies (yes, more fairies) flitter about her bed.
Those last two lines are a little weird: they definitely refer to the magician Merlin from Arthurian legend, but critics are a little fuzzy on exactly which episode of Merlin's life they reference. Most think the lines are talking about Nimue—the witch that Merlin had a huge crush on, but who ended up trapping him in a cave, where he died. Sad.
Confusion aside, everybody agrees that this last part definitely sets a sinister tone, and ratchets up the tension.