History of Magic was by common consent the most boring subject ever devised by wizardkind. Professor Binns, their ghost teacher, had a wheezy, droning voice that was almost guaranteed to cause severe drowsiness within ten minutes, five in warm weather. He never varied the form of their lessons, but lectured them without pausing while they took notes, or rather, gazed sleepily into space. The only reason any Slytherin passed was because they had notes passed down from 2 centuries ago when the classes were proper, and copies of the old test questions. Today, they suffered an hour and a half's droning on the subject of giant wars. Hermione chose to read about her Ward Potion.