It's the end of an era. Since 2000, we've had the perfect Professor X in seven of the X-Men films. No matter how exciting or flawed the films were, we could always trust that Sir Patrick Stewart would bring a sense of depth. He fit the role perfectly but as he recently announced, he's retiring as Professor Charles Xavier. He said the decision came after a screening of "Logan" in Berlin, after which he was so moved by the farewell given to the character of Professor X that he decided then and there to make it the last one.

RELATED: Patrick Stewart is Retiring From X-Men Franchise: ‘I’m Done’

We feel it's only fitting that we take a look back at Stewart's time as Charles Xavier, a character he's played in seven films over the course of 17 years. Without further ado, we give you his 15 most memorable Professor X moments.

15 CONFRONTING MAGNETO

Professor X Magneto Film

We were introduced to Patrick's Xavier in "X-Men" (Directed by Bryan Singer) when he confronted Magneto during the Mutant Registration Act hearing. The scene perfectly established the conflicting views between the two, as well as the existence of a shared history. Xavier tries to persuade Erik to forgive humanity (which is definitely not a small ask), but Erik is steadfast in his need for vengeance and mutant domination.

Patrick Stewart, back then (nd perhaps still) best known for his role of Captain Jean-Luc Pacard, brought that much-required steadiness to the character. As he speaks, he does so with conviction; and yet, when faced with Magneto's hate and unwillingness to give humanity a chance to accept mutants, Stewart gives us Xavier's patience and understanding. That's why it's such a great introduction and one of the reasons why Stewart is, and will always be, the perfect actor to play such a famous comic book character.

14 INTRODUCING LOGAN

Logan Meets Xavier

It was an awesome moment when we were introduced to Xavier's powers through Logan (Hugh Jackman). Charles led the confused Wolverine through the basement of the X-Mansion to his office, all while he conducted a meeting with his students. He lets Logan see what the school for gifted students is about and tries to show him that he isn't so different, and that he isn't alone. It's a fun little taste of the Professor's psychic powers and his ability to multi-task while using them.

Maybe it's the calm in Patrick Stewart's voice (which, let's face it, makes any monologue sound awesome) that makes this scene, how it emanates with a sense of control; or maybe it's how he seems to handle the situation almost nonchalantly, as though he's been through this many times and he's used to it. It's all very subtle but it's easy to see Xavier as a leader from here on, even if you haven't seen Star Trek.

13 MAGNETO'S LACKEYS

Sabretooth Film Possessed

One of the great things about a character like Xavier is the fact that he knows how powerful he is and what he's capable of, which is why he so often holds back. We see him push our expectations more and more throughout the first "X-Men" film until we get to that epic scene when Magneto has his little stand-off with the police and ends up holding them all hostage. Xavier, given no other choice, completely possess Sabretooth and Toad to talk to Magneto who, as you might have guessed it, does not relent.

If anyone had any doubts about the power Xavier possessed, this scene would prove them wrong. It highlights how dedicated he is to the good fight. It's not that he can't easily win, it's that he wants to do it right -- something that Stewart subtly shows in his performance, looking morose as he knows he cannot follow through on his bluff of killing his friend. The ache of it is so brilliantly expressed on his face, it's clear how difficult it is for him to just to hold back sometimes.

12 CHESS

Professor X and Magneto playing chess in X-Men.

There are few relationships more entertaining to watch than that of Charles Xavier and Erik Lensherr, who are caught halfway between friendship and enmity. How many other foes can sit down and enjoy a peaceful game of chess after one has just landed the other in a seemingly inescapable prison cell as these two did at the end of the first "X-Men" film?

It was brilliance on the part of Bryan Singer and the screenwriter to include this dialogue over a game of chess. When spoken by Stewart and Sir Ian McKellen -- two famous friends in real life -- the subtle duel between cynicism and hope is enough to make this scene downright iconic. You might even go so far as to say that even if the rest of the movie didn't happen, or if it simply began with this scene, the drama could still be felt, thanks to the effect of these two and the immense conviction they're able to convey.

11 USING CEREBRO

Cerebro

As powerful as he is, even the great Professor X can't connect to every mind in the world on his own. That's why he built Cerebro (with the help of Magneto back when they weren't enemies). Cerebro is a giant room and machine which amplifies Xavier's psychic powers, allowing him to connect to every mind on the planet (assuming they're not wearing special metal helmets). It was fantastically depicted in the film and made for quite the memorable moment in "X-Men."

Though it's focused on him and his powers, this moment wasn't really about Charles Xavier. Still, you have to respect Stewart's decision to act out the scene without the slightly overly-dramatic cringing or sense of struggle any other actor might have tried to employ. That's the mark of an experienced actor -- knowing when less is more. Stewart's Xavier isn't struggling with anything here; when he uses Cerebro, it's smooth sailing.

10 DESTROYING EVERYONE

X2 Stryker Cerebro

Xavier told Wolverine in the first film that if he were to concentrate too much of his power in Cerebro, he could kill someone. All that power, usually held in check by Professor X, can still fall into the wrong hands. "X2" (directed by Bryan Singer) showed us precisely that when William Stryker used his son's powers to manipulate Xavier and compel him to try and eradicate all mutants. When the X-Men and Magneto arrive to intervene, Magneto, protected by his helmet (which he totally pulls off), takes the opportunity to manipulate Xavier into trying to eradicate humans instead.

It's not Xavier's best moment, but Stewart is able to portray the character in that moment as helpless and somewhat confused without really sacrificing his stronger qualities. He becomes an object of incredible power, caught in the struggle for control over the world between humans and mutants, amazingly enough coming close to destroying both.

9 THE PHOENIX

X2 Charles Xavier Phoenix

We make mistakes and are each capable of doing terrible things for the greater good. Xavier is no different. In "X-Men: The Last Stand" (directed by Brett Ratner), we find out that sometimes, despite his best efforts, some mutants just have no hope of controlling their powers. That's why he suppressed Jean Grey's more powerful Phoenix persona through psychic manipulation, a reveal that left us as shocked and surprisingly disgusted as Logan when Xavier revealed it in the film.

It's disappointing that he was forced to use his psychic powers in such a dark way, but completely understandable that he had to, which is exactly why we still believe in him after that revelation. Even if it was a mistake and there were vague (though admittedly difficult and unreliable) alternatives, the Professor had no evil intentions behind his actions and only acted because he could foresee the destruction the Phoenix was capable of, something we catch a glimpse of in the climactic ending of the film.

8 XAVIER'S DEATH

Charles Xavier Dies in X3: The Last Stand

It's the mistake her makes in dealing with Jean that makes this explosive (in more ways than one) death scene so interesting. He and Magneto walk into the Grey house, both intending to win her over to their side. Xavier does his best, but the Phoenix already has it in for him for trying to hold her back and keep her true power at bay. Despite Xavier's best efforts to help her, she raises him out of his chair and brutally destroys him, pulling him apart seemingly on an atomic level.

Stewart's intensity is the reason this scene has so much power. You can hear the desperation in his voice and the quiet resignation that he's lost this one. Another interesting thing to note about this scene is the smile Charles gives Logan just before he's destroyed. It could have been the acceptance of death before his body was obliterated, or it could have been because he knew that this was not to be his final moment.

7 XAVIER RETURNS

Xavier Returns X-Men The Last Stand

They hinted at it quite early on in the film when Professor X was giving a lecture to his students about their mutant powers and the ethical dilemmas they might encounter. In his example, he posited an ethical dilemma about survival for a psychic who would completely possess the body of a comatose man whose consciousness was essentially lost. In the post-credits scene of "X-Men: The Last Stand," Moira MacTaggert is greeted by her comatose patient waking up and she quickly discovers that it is in fact Charles Xavier, back from the dead.

It's quite a short scene and Patrick Stewart has only one line in it, but that's more than enough to provide us with the shock needed to make this a thoroughly satisfying plot twist, even if it does completely detract from any real drama caused by his earlier death scene. It is Xavier, after all, he can't stay dead. Cyclops on the other hand... well, sorry Scott, but at least you came back after "Days Of Future Past!"

6 GUIDING PRISONERS

Xavier Returns X-Men The Last Stand

Charles Xavier manages to surprise in quite a few ways, even if it's just by making a small appearance as he did in "X-Men Origins: Wolverine," in which he helped get lost mutant prisoners off Stryker's terrible island. Among the mutants saved were Kayla's sister (who definitely wasn't meant to be Emma Frost), Cyclops and a lot of other mutants that day when he showed up walking from his helicopter.

For most of this scene, we just hear Stewart's voice giving directions directly to Scott, and while it might have been a mystery for some, others would have immediately guessed who it was that had arrived to save the day while Logan was out fighting the mistake-without-the-mouth. It doesn't matter how he knew about this place or why he's walking again (one of many continuity errors apparently solved through "X-Men: Days of Future Past"), what matters is he was there and it was awesome.

5 REVEALS HIS SURVIVAL

Xavier The Wolverine

"The Wolverine" (directed by James Mangold) was a lot better than its predecessor, partially because it focused on Wolverine (like a Wolverine movie should) instead of shoving familiar characters in our faces. That being said, this one mid-credits scene where Logan encounters Magneto in an airport was a brilliant little teaser of what was to come. Xavier does his thing and freezes the minds of everyone in the security checkpoint before rolling out and revealing that he's been alive and well. While most of us knew that already, it was a fantastic reveal nonetheless, though it did raise a few questions.

This is just pure Patrick Stewart returning to the X-Men franchise after a brief hiatus due to his character kind of dying. Of course, he does so in style (with the mind-freezing and that sharp looking suit). With one line, he brings back memories of the original movies, making this quite a sentimental moment; then, without saying a word about it, Xavier hints at the terrible future he and Magneto are trying to prevent.

4 TRUSTING WOLVERINE

Logan Older Xavier

The world has become a mutant-hunting nightmare in "X-Men: Days of Future Past" (directed by Bryan Singer) and the only way to save it is to send Wolverine's consciousness back to the 1970s and prevent Bolivar Trask's sentinels from ever being unleashed. Even though Wolverine isn't exactly the most patient person in the world, and this is in no way an assassination mission (quite the opposite, in fact), Xavier shows nothing but complete faith in Logan.

Stewart maintains an expression of determination with that little hint of doubt, as though he doesn't place faith in this just because he can, but because he has to. He watches Shadowcat (Ellen Page) transfer Wolverine's mind through time (because she can do that now, apparently), hoping that it will work and trying his best to reject Magneto's doubts about their younger selves' willingness to heed Logan's warning. Even though Stewart (and all the original characters) are only in the film for what amounts to a handful of minutes, he still manages to make the scene that leads into the rest of the film, so it isn't just some dull intro we have to get through.

3 RESTORES FAITH IN HIMSELF

Xavier Meets Xavier

Of course, Logan isn't really one to easily restore faith in people and he knows that. In fact, he admits that willingly to the younger Xavier (James McAvoy) and tells him that the only reason he was there was because his mind wouldn't break through the trip. Logan does serve another purpose, however. He's the conduit through which we're given one of the best scenes in the "X-Men" franchise: Xavier talks to his younger self.

There aren't a lot of similarities we can see in Stewart and McAvoy's performances, but that makes sense since Stewart plays a more mature Xavier, shaped with the powerful experiences he's had to fight through. It shows in the way he talks to his younger self. He's a friend and a guiding hand; basically how he is to every student he's had. Therein lies the essence and possible origin of the character's understanding of growing mutants. He was just as lost and just as afraid of his powers as the rest of them, but it was confidence in himself (from himself, technically) that pushed him through it.

2 BURYING THE HATCHET

Magneto Xavier Make Peace

For a while there in "X-Men: Days of Future Past," all seemed like it would be lost. The sentinels had butchered everyone and they were literally at Xavier and Magneto's doorstep. A wounded Magneto lay in front of Xavier dying and feeling a bit nostalgic, realizing what a waste it had been fighting each other all those years. Xavier doesn't say a thing but offers a hand in a gesture of true friendship and forgiveness.

Stewart has no lines but his expressions are powerful enough to perfectly convey his feelings. In the beginning, you can't really tell if he does forgive his old friend for all the hostility and death that surrounded his bitter campaign against humanity. He wears an almost angered look, one that slowly fades as he hears how Magneto regrets. It's acting at its finest when you can just about tell exactly what a character is thinking without ever having to hear it expressed -- a suitably appropriate explanation of Xavier himself, interestingly enough.

1 MEETING LOGAN (AGAIN)

Charles Xavier Revelation

Unti "Logan," (directed by James Mangold), this was the last scene we were given of Charles Xavier and his school for gifted youngsters. It was a fitting last scene that begins with Logan waking up to find that everything is relatively normal again. Scott, Jean, Storm and Hank are all there and his world is at peace. His mind, however, is at a loss and it's up to Xavier to set things straight.

The purpose of "X-Men: Days of Future Past" seemed to be resetting the universe in the franchise, which means Logan's actions in the film shifted and saved a lot, it was only right that someone knew about it and it's fitting that it was Xavier who discovered the change first. The shock on his face and grateful smile was just the right touch to the sentimental scene, which also helped to act as a passing of the torch from the original cast to the new one. It still seemed like too little for Patrick Stewart's Xavier, which is why we're hoping that the new "Logan" really does give him a well-deserved farewell.

What were the moments that most made your mind reel in Sir Patrick performance as Professor X? Let us know in the comments!