Our Cats were 5yrs old when we introduced 8 week old GSD pup Max to them.... and Max soon learnt that Cat = Boss, when Budweezer was alive they used to have spectacular fights,Bud was evil would never leave him alone, everytime he walked past Max he had to have a pop at him, even if Max was curled up alseep.
Was really sweet though the last couple of weeks of Budweezers life, he'd follow Max about and sit inbetween Max legs, even if Max was eating Bud would be there and as soon Max curled up on his bed, Bud would curl up alongside of him, I swear it made him feel secure and protected with Max, and i'm sure Max could sense he was poorly, he used to hate Bud going anywhere near his bed ( so of course Bud knew it and would sit there just to wind him up ) but not when Bud was ill, he was happy to have him there cuddled up to him