You will find ambiguity a great ally on your road to power. Give a sign of Slytherin on one day, and contradict it with a sign of Gryffindor the next; and the Slytherins will be enabled to believe what they wish, while the Gryffindors argue themselves into supporting you as well. So long as there is uncertainty, people can believe whatever seems to be to their own advantage. And so long as you appear strong, so long as you appear to be winning, their instincts will tell them that their advantage lies with you. Walk always in the shadow, and light and darkness both will follow.

Harry was speeding toward the ground when the crowd saw him clap his hand to his mouth as though he was going to be sick-he hit the field on all fours-coughed-and something gold fell into his hand. ‘I’ve got the snitch!’ he shouted, waving it above his head, and the game ended in complete confusion. ‘He didn’t catch it, he nearly swalloed it,’ Flint was still howling twenty minutes later, but it made no difference-Harry hadn’t broken any rules and Lee Jordan was still happily shouting the results-Gryffindor had won by 170 points to 60.

Another ten points from Gryffindor, said Snape. I would expect nothing more sophisticated from you, Ronald Weasley, the boy so solid he cannot Apparate half an inch across a room.

Where are you heading, if you’ve got the choice? James lifted an invisible sword. ‘Gryffindor, where dwell the brave at heart!’ Like my dad. Snape made a small, disparaging noise. James turned on him. Got a problem with that? No, said Snape, though his slight sneer said otherwise. If you’d rather be brawny than brainy — Where’re you hoping to go, seeing as you’re neither? interjected Sirius.

Gryffindor, where dwell the brave at heart!

By Gryffindor, the bravest were Prized far beyond the rest; For Ravenclaw, the cleverest Would always be the best; For Hufflepuff, hard workers were Most worthy of admission; And power-hungry Slytherin Loved those of great ambition.