I just listened to this lyric a number of times and it still sounds more like "fifteenth" then "thirteenth." I'd caution you against thinking that lyric sites are always correct, even when by an artist. That's like saying the guitar tab always matches the music. Often it doesn't. My guess is you are not truly listening and are relying on secondhand information. Listen carefully...the word in question opens with an "f" sound, not a "th"... also I don't hear an "ir" in there. Seriously. I think Pete Hamill started all of this with his original BOTT album notes where he references Dante and everyone just ran with it. Anyways - 'nuff said, go my way or accept your own received wisdom.

chuckleface