I have a large dog. Great Pyrenees.
He has nothing but love in his heart for all small animals. He wants to guard them. It fulfills him to simply be near them. It is his programming.
I have cats. They are dicks. I try to acclimate them to the dog by sneakily (while petting them) putting them on top of the dog, like in the above photo, and holding them there by their scruff for a few seconds.
I figured the cats would realize that they can be friends, and after a while, I’d come home from work and find them spooning. you know, like in a calendar photo.
No dice thus far.
They’ll get along just as soon as the dog learns he is their servant and the cats are the masters :)