Iris finally has a real doggie friend

Shortly after bringing Iris home from the shelter we found out she hates other dogs.  Especially small dogs, although she once attacked Hawkeye, my daughter's dog who is far bigger than she, to the point where he didn't want to come and visit us for a long time.  
It was really frightening when she attacked Cliff's sister's miniature dachshund, Angel, because that sweet little dog always submits to other dogs and loves everybody.  Honestly, it was downright scary when Iris attacked her.  We're not just talking about a grumpy old dog that snaps at others; Iris obviously meant to kill, and we had to tear them apart.  
She finally stopped attacking Angel, although I'd still be hesitant to leave them alone.  She has never accepted the other dog that lives with Angel, and went viciously after her not too long ago; once again, if someone had not been there to intervene, I don't know what might have happened.   
So, my grandson has been working lots of overtime, and he's been having his girl friend bring their Great Dane pup out here to spend the day.  He's no problem at all.  He stays near our house, spending lots of time sleeping on the porch.  I let him in a few times a day and he does well, mostly just following me from room to room; no accidents so far.  
Iris has never shown her usual bad attitude with Titan.  He's big and clumsy, and tries to force her to play; you'd think if she was going to attack anybody, it would be him.  But after two weeks being forced to put up with Titan, the most she has done is snap at him when he stumbles over her.  
Maybe she realizes he's just a puppy.  

Not only that, but I've seen her outside playing with him.  Yes, she likes the big oaf.