From what I understand, waaay back when (like around 2002 or so/Eminem Show era), Em mentioned having having dated Mariah on "Superman" and "When The Music Stops".
Allegedly, this went on for months but when Mariah spoke on it publicly, she played it low like, "We talked a few times and hung out, but didn't date."
Down the line, she drops subs on a song ("Clown") and essentially says that they'd never touched one another and had an Eminem puppet at her show.
Em (basically): "...I got voicemails though. Don't try to play me out here and lie."
50 weighs in on a song.
50 (basically): "Em told me these Hollywood hoes are liars."
So, Em & Mariah aren't too fond of one another (and they're clearly both crazy) and he's like, "Nick, good luck with the fukkin' whore" on the Relapse album.
I think Nick is married with the Mariah tattoo on his back at this point. He doesn't take too kindly to this and goes on a rant. Deletes it.
Mariah drops "Obsessed" with the implied Eminem in the video. Em drops "The Warning" where he actually splices in the voicemails he was talking about, tells Nick to fall back, and mentions Mariah's alcoholism and how they smashed and came early on, much like the final B-Rabbit freestyle in "8 Mile". I think he says in the beginning of the track that he was going to let it all slide until she denied ever seeing him.
shyt was brazy.
Nick spoke on the Em thing with T.I. on T.I.'s podcast. Eminem said something on this "Lord Above" track on Fat Joe's new album...basically: "I told you she was crazy. You were too whipped. shyt, I was too."
...and now we're here with Nick's diss and 50 thinks Nick is wylin' out to be battling Em.
Don't even.