Anti-Dementor lessons

"A Patronus is a kind of positive force, and for the wizard who can conjure one, it works something like a shield, with the Dementor feeding on it, rather than him. In order for it to work, you need to think of a memory. Not just any memory, a very happy memory, a very powerful memory… Allow it to fill you up…lose yourself in it…then speak the incantation ‘Expecto Patronum.’"

- Remus Lupin

In 1994, Remus Lupin, then-Professor of Defence Against the Dark Arts offered to teach Harry Potter how to perform the Patronus Charm. The class took place in the History of Magic classroom. Lupin managed to locate a boggart inside Hogwarts Castle, which he then placed inside of an old trunk. When the trunk was opened in front of Harry, the boggart would take the form of his worst fear, a dementor, on which Harry would then attempt to perform the Patronus Charm. Although the dementor was fake, it still produced similar effects on Harry, and Lupin would give him some chocolate after each lesson. Harry took several of these lessons with Lupin before he eventually succeeded in creating a non-corporeal Patronus.

Background information


In the summer of 1993, Sirius Black, the most infamous prisoner in Azkaban, escaped from the prison. When informed of this situation, Minister for Magic Cornelius Fudge took many proactive measures in order to corral Black once more. Among these were informing the Muggle Prime Minister and deploying the Dementors into the countryside to search for him.

At the beginning of the school year fearing that Black might attempt to kill Harry Potter, Fudge dispatched the dementors to protect Hogwarts School of Witchcraft and Wizardry and search Hogsmeade village. On September 1, the Hogwarts Express was searched by the dementors. When a dementor reached Harry's compartment, it began to feed off the human emotions as usual. Harry was uncharacteristically affected by its presence. He began to have a fit and could hear a woman screaming in his head. Ginny Weasley was also greatly affected. Harry and company felt better after Professor Lupin had driven the dementor off and given each of them chocolate.

Glad to be rid of the dementors, Harry had to deal with a great deal of taunting from fellow students over the incident, especially Draco Malfoy and his cronies. Harry did not have another run in with a dementor until his first Quidditch match versus the Hufflepuff Quidditch team. The dementors invaded the match seeking a feast on the high running emotions. However, they found Harry. He was once again greatly affected and fell fifty feet from his broom.

The lessons


Knowing that he had driven the dementor away on the Hogwarts Express, after the Quidditch match, Harry asked Professor Lupin to help him fend off the dementors. Lupin was initially reluctant, but after seeing Harry's determination, he relented. However, Lupin told Harry that their lessons would have to take place after the Christmas holidays as he was under weather (affected by his lycanthropy, but Harry was not to know this).

They began their first lesson early in January in the History of Magic classroom. Professor Lupin had procured a Boggart from Caretaker Filch's office. When he explained to Harry that the boggart would take the form of a dementor and that it would create a more real experience, Harry was slightly scared, but tried to sound reassured. Before he released the boggart, Lupin taught Harry the incantation, Expecto Patronum, and gave Harry a short lecture on the Patronus charm and its effects. Then he told Harry to concentrate on one single happy memory, and when Harry informed him that he was ready they tried it once and Harry conjured a thin whisp of vapour. Next, Lupin unleashed the boggart.

Harry tried many times to conjure a patronus, but he failed and soon collapsed. Lupin feed him some chocolate and asked if Harry still wanted to continue. Harry, of course, was not going to quit, so they tried again after Lupin told Harry to pick a stronger memory. The result was the same, but Harry did not want to stop, even though Lupin was having reservations. Once more they tried, after Harry had picked another memory, and Harry managed to produce a shield. He was putting all of his strength into holding the dementor-boggart at bay, when Lupin banished it. Lupin was happy that Harry had managed the spell, but it cost Harry all his strength.

After a few lessons, Harry lamented his lack of progress. He said that he hoped that he could conjure something that would drive the dementors away instead of just shielding him. Lupin told him that a true patronus would do just that, but for a thirteen year old wizard Harry was doing extremely well and should be able to reach the ground should the dementors made another appearance at a Quidditch match. It was during a Quidditch match that Harry produced his first corporeal patronus. When some Slytherin students attempted to sabotage him as he flew for the Golden Snitch, he conjured a Stag patronus that chased the "Dementors" away.

Aftermath


Harry would be called upon to use the Patronus charm in a life threatening situation soon enough. In June, Harry discovered that his godfather, Sirius Black, had not in fact betrayed his parents, but it was Peter Pettigrew who performed that dastardly task. For a glorious half hour, Harry believed he would finally be rid of the Dursley family. That was snatched away when Pettigrew escaped, and the dementors found Sirius on school grounds. Harry and his friend Hermione Granger tried to defend Sirius from them, but after holding out briefly, his patronus shield was overcome by the dementors one of whom tried to use the Dementor's Kiss on Harry. They were driven away by a powerful patronus, but Harry could not identify his savior. When Harry and Hermione used the Time-Turner to go back in time, Harry discovered that it was he who had cast the patronus that saved his, Hermione, and Sirius's lives. He then cast the spell driving nearly one hundred dementors off.

"If I'm proud of anything I've done this year, it's how much you've learned.... Tell me about your Patronus."

- Professor Lupin addressing Harry's Education

The following morning when Harry went to speak with Professor Lupin who Harry had just discovered had resigned, Lupin asked him about his patronus. After Harry told him, Lupin confirmed Harry's supposition that his patronus was "Prongs," and he told Harry how proud he was to have taught Harry so much.

Behind the scenes

 * In the film adaptation of Harry Potter and the Prisoner of Azkaban, Harry only took one of these lessons from Lupin instead of the several mentioned in the book. In addition, in the film Harry was able to produce a non-corporeal Patronus on only his second attempt.

Appearances

 * Harry Potter and the Prisoner of Azkaban
 * Harry Potter and the Prisoner of Azkaban (film)
 * Harry Potter and the Prisoner of Azkaban (video game)