`I neither like nor dislike Severus', said Lupin...'We shall never be bosom friends perhaps; after all that has happened between James and Sirius and Severus, there is too much bitterness there. But I do not forget...Severus made the wolfsbane potion for me, made it perfectly HBP, p312 uk, ch A very frosty Christmas. (Harry talking to Lupin)  Have you ever heard of the Half-Blood Prince?...I've got his old potions book. He wrote spells all over it, spells he invented. One of them was levicorpus'. 'Oh, that one had a great vogue during my time at Hogwarts.' said Lupin reminiscently. 'There were a few months in my fifth year when you couldn't move for being hoisted into the air'.  'My dad used it', said Harry...Lupin's smile was a little too understanding. 'Yes', he said, 'but he wasn't the only one...James was a pure-blood, Harry, and i promise you, he never asked us to call him ``Prince'.  'And it wasn't Sirius... or you?' 'Definitely not. How old is this book, Harry?... perhaps that will give you some clue when the prince was at Hogwarts. HBP p315-316 uk, ch A very frosty Christmas (Harry talking to Lupin)  `