Dumbledore aside, the debate on who Hogwarts' most powerful professor was in the Harry Potter series lies between Minerva McGonagall and Severus Snape. The series boasted an array of experts in the magic arts, with the professors at Hogwarts constituting a large majority of them. Dumbledore's position as the most powerful professor in Hogwarts is undeniable, but the extent to which McGonagall's impressive dueling skills can stack up to Snape's expertise in Legilimency is up to question.
In Harry Potter and the Sorcerer's Stone, it was clear the rivalry between McGonagall and Snape over Harry Potter was rooted in their mutual respect for Dumbledore. When McGonagall took Harry to Snape's quarters in Harry Potter and The Order of the Phoenix after a flurry of nightmares about Voldemort, it showed she trusted Snape's skills to aid Harry to overcome such nightmares. Though the extent to which she knew of Dumbledore and Snape's plot against Voldemort is debatable, their mutual respect for one another indicates the significant power they held as masters of the magic arts. For example, in Harry Potter and the Deathly Hallows – Part 2, Snape was reluctant to fight McGonagall when the latter took him to a duel in front of Hogwarts students.
Related: Harry Potter: Every Clue That Snape Wasn't A Villain
Both characters had their strengths, but the last Harry Potter movie proved Snape was the strongest Hogwarts professor. McGonagall's transfiguration reputation spoke for itself. She was able to morph herself into a feline, making for that comical moment in The Sorcerer's Stone when Ron thought he was safely in time for his lesson and could manipulate any animal into stationary objects. However, Harry Potter and the Half-Blood
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