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Franchise favorite Harry Potter and the Prisoner of Azkaban was a game changer. Chris Columbus stayed on as producer while Oscar winner-in-waiting Alfonso Cuarón (Roma) took over. With him came a tonal change that altered this franchise and unleashed dementors forever. Not only that, but he introduced Azkaban’s most infamous inmate Sirius Black, intent on tracking down Harry Potter and delivering a death sentence for crimes against the dark lord.

Beyond the threat of an unstable Azkaban inmate circling Hogwarts, this installment also gives audiences another appointee to the post of defense against the dark arts. Professor Lupin may have been more equipped than his predecessor to tackle this topic, but he conceals an affliction far worse than vanity. Linked to the lunar cycle and an inherent fear of animalistic amnesia, his arrival really opens things up. However, beyond a bloody-thirsty animagus out for revenge, soul-sucking dementors, and a dark arts professor who should avoid moonlight, Azkaban brings more to the table. Having just celebrated its 20th anniversary, now feels like the right time to look back on why this entry is still so popular.

Sirius Black Will Be Gary Oldman’s Legacy

Professor Lupin Is a Truly Tragic Figure in Harry Potter

• The first choice to play Sirius Black was actually British actor Robson Green.
• The name Remus comes from Roman mythology and harks back to its founders, Remus and Romulus, who were both raised by wolves.
• Sirius was named after the dog star, found in the constellation Canis Major and said to be 26 times brighter than the Sun.

There is no denying the importance of Sirius Black to Harry Potter. His introduction and the actor who embodied him have become legendary. Gary Oldman may have won an Oscar for playing Winston Churchill in The Darkest Hour, but Sirius Black will be his legacy. Painted as an outcast and defined by his thirst for revenge, Black is only glimpsed on posters, spoken about in whispers, and associated with evil at every turn. That his eventual arrival reveals a paternal figure who only wants the best for his godson Harry is ironic.

At the core of this character is something truly tragic. An animagus blessed with an undeniable humility that Oldman revels in, allowing the wider wizarding world to label him a killer rather than admit their mistakes. Imprisoned for murdering Peter Pettigrew and some innocent bystanders, Black gives up 12 years of his life to Azkaban. Compelled to protect Harry from he who must not be named, Sirius escapes with the sole intention of protecting his godson. Although those circumstances are never directly revealed, along with other critical plot points, Sirius is spurred into action by a simple act of forgiveness from Harry.

Remus Lupin also has his own air of tragedy that sees him cast out for being different. A lifelong friendship with Sirius Black, although afforded no backstory, provides Remus with some degree of solace from his plight. Slave to the lunar cycle that sees Lupin transform and literally lose his mind, their bond goes deeper than common ground. Having been bitten at age 5 in revenge for a personal insult against the werewolf community, Lupin is forced to endure physical changes that go beyond adolescent growing pains. Brutal, humiliating, and unpredictable, his condition has resigned him to years of suffering. Punishment for that childhood transgression seems to be an endless cycle of physical changes which he treats like some form of penance. That David Thewlis is able to convey that conflict and bring a degree of selflessness to his performance is impressive. Yet, despite these horrific transformations that consume his every waking hour, this idea of perpetual change is possibly the important theme addressed in Harry Potter and the Prisoner of Azkaban.

Alfonso Cuarón Changes Everything

The Prisoner of Azkaban Does More Than Take Things in a Different Direction

• Ian McKellen turned down the role of Dumbledore because Richard Harris criticized his acting.
• Cuarón's wife and daughter appear in a portrait during the film.
• He asked Daniel Radcliffe, Emma Watson, and Rupert Grint to write him essays about their characters during production.

Beyond the sad but essential replacement of Richard Harris for Michael Gambon in the role of Albus Dumbledore, Azkaban is as much about change as transformation. Nowhere is that plainer than among the youngest cast members, who grow up throughout this franchise and incorporate it into their performance. Within Azkaban especially, the differences between Daniel Radcliffe, Tom Felton, and Emma Watson are unavoidable, since adolescence has such a radical impact on them all as actors. This change not only occurs with the cast but is reflected creatively by director Alfonso Cuarón. His decision to adopt a low-key color palette over something more vibrant gives Azkaban a distinctive look that moves away from Chris Columbus on so many levels. Hogwarts becomes an eerie place filled with shadows where the unwary could come unstuck. An overwhelming sense of foreboding makes this school for witchcraft and wizardry feel oppressive, as driving rain or blankets of snow alter its architecture. Cuarón also ensures that audiences are reminded of the dementors at every opportunity, subconsciously influencing the mood and pushing this franchise in an adult direction.

His visions also extend to the story itself, where for the first time it became plain how many characters in Harry Potter are physically or emotionally broken. Bullied, belittled, or weighed down by expectations - each one has their own demons to fight. For Professor Snape, the re-appearance of Lupin in his life conjures up old memories, forcing him to confront an old tormentor and re-live his role as victim. In a masterful moment from Alan Rickman, which is rarely seen again, audiences catch a glimpse of how deep those psychological scars really go.

Outside a focus on personal journeys that subtly change the tone, exterior locations also feel more grounded as moments spent in Hogsmeade reveal a real sense of community. That literal change is also reflected in the introduction of a marauders map, able to transform at a whisper of the words mischief managed. This map is another metaphorical change that alters Harry’s perspective and tips a hat to the book by highlighting Moony, Wormtail, Padfoot, and Prongs. Without this, Harry would never learn about Peter Pettigrew, overhear Cornelius Fudge, or access the screeching shack to confront Sirius Black.

Harry Potter Continues Switching Genres

Daniel Radcliffe Continues to Grow into the Role

• Daniel Radcliffe initially turned down the role of Harry Potter
• His contract from Warner Brothers was only for the first two films.
• He first caught the eye of producers, when Chris Columbus saw him in a BBC adaptation of David Copperfield.

Harry Potter and the Prisoner of Azkaban also chops and changes genres, switching between a prison break, a rite of passage melodrama, and an introspective character piece. As the franchise expands and its ambitions become more profound, it is almost impossible to categorize Harry Potter as one thing. At this point, it is fair to say audiences are in the presence of a phenomenon that only continues gaining momentum. Harry Potter and the Order of the Phoenix may already be written, but anticipation for every film was at a fever pitch, and it all started here.

However, this is also the point at which Daniel Radcliffe started showing his mettle. Having faced down 30-foot snakes and battled malicious professors, suddenly those heroics become more character-based. This is when the actor comes out and that boy wizard evolves into a screen actor. The transformation might not be fully complete for another installment, but just as Azkaban marked another turning point in this story, so too does it herald another phase in Radcliffe’s professional growth. Surrounded by legends of the stage and screen for several years, it was inevitable that something transformative would occur. Sirius Black might have been a paternal figure in Harry Potter and the Prisoner of Azkaban, but there is no doubt Gary Oldman made sure to take care of Radcliffe off-screen too. With some of the finest acting coaches working with him, from now on Harry Potter becomes as interesting for its story as for the evolution of Daniel Radcliffe. Azkaban might be defined by personal tragedy, physical transformation, and adolescent growing pains, but it is also a towering achievement. With a change in director and the replacement of an integral character actor, Harry Potter and the Prisoner of Azkaban still manages to be one, if not the most impressive entry in this franchise.