Of course, it is ironic that Snape's Patronus would also take the form that complimented that of his oldest enemy. The Harry Potter series makes it clear that the Potions Master despised James ...

Much like Harry Potter, his father, James Potter, had a Patronus that took the form of a Stag. James' son inherited the stag Patronus from him, and since Harry's took the form before he knew his ...