Harry Potter and the Surprisingly Competent History of Magic Professor

Cassian pulled out his wand and flicked it. The air shimmered as a golden haze spread across the room, swallowing the office whole. The walls of stone vanished, replaced by a vast battlefield under a storm-dark sky. Wizards in ancient robes clashed with glowing blades of raw magic. Smoke curled from the ground where curses had struck, and above it all, a woman stood… Morgana stood tall, her cloak pooling behind her like spilled ink in the mist.

She raised her hands, and the storm above obeyed. Lightning cracked, splitting the battlefield apart, and with a single command, her forces surged forward, cutting through the enemy ranks like fire through parchment. It was war, but not the version in children's tales… this was blood, chaos, and magic wielded for ruthless ambitions.

Cassian let it linger for a moment before flicking his wand again. The vision faded.

The room settled back into itself, though the silence stretched.

McGonagall's lips pressed thin, hands clasped tighter than necessary in her lap. Flitwick looked impressed. Sprout thoughtful.

"Typical," Snape murmured, his voice dripping with disdain. "A Rosier glamorising a witch who despised Muggles. How refreshing."

Dumbledore tilted his head. "You seem to have cast Morgana in quite a… favourable light, from what I hear."

Cassian shrugged. "She was one of the most powerful witches of her time. That doesn't change just because she wasn't on the 'right' side of history."

Snape scoffed. "Fascinating, truly. A Pureblood downplaying Morgana's views on Muggles. What a refreshing turn of events."

Cassian turned his gaze on him. "History's never been black and white, Severus. Only fools and propagandists believe otherwise. You can despise someone's ideology and still acknowledge their skill. Or would you prefer I sanitise it and pretend she was just a cackling villain throwing curses in the dark?"

Dumbledore interjected before Snape could respond. "An interesting perspective, Professor Rosier. One that I imagine has certainly given your students much to think about."

Cassian nodded. "I know where your distrust comes from, and I agree that as teachers, we shape how students see the world. That is why I never liked how Binns taught… he was biased against anything nonhuman, made sure students saw goblins, centaurs, and merfolk as footnotes in wizard history rather than actual players." He leaned back. "I don't praise Morgana, and I don't embellish her fear and hatred of Muggles. I show what shaped her. In her time, being a woman was already difficult, being a witch was worse. Wizards were kings, heroes, scholars. Witches were shadows, healers, whispers in the dark. If they stepped out of line, they weren't just punished… they were erased."

"A perspective I imagine not all parents would appreciate," McGonagall said coolly, though a glint in her eyes betrayed her approval.

Flitwick gave a small nod. "I daresay students are learning more than just dates and names in your class, Professor Rosier."

"Apparently too much," Snape muttered.

Cassian didn't bother responding. He wasn't about to waste time debating Snape's fondness for rigid, mindless teaching. Instead, he turned to Dumbledore.

"As a historian and the History of Magic professor at one of the best wizarding schools in Europe, I would say it is my job to provide context… how spells came to be, how different magical communities thought, and how these spells were used," he said. "And, as I repeatedly remind my students, none of this is mandatory. Those who want to further their magical masteries can complete additional assignments at their own discretion."

McGonagall gave him a long look, then nodded. "As long as it is clear where the boundaries lie."

Cassian spread his hands. "Crystal."

Dumbledore nodded. "I believe, as you put it, this is still within the scope of your title. And as long as your methods aren't dangerous, we have no reason to limit how you teach. From what I've seen, you've done a rather good job."

Cassian shrugged. "Glad we are in agreement."

They went over a few more things. Cassian pointed out something he had already covered in his Summer Festival lecture… magic wasn't just about flicking a wand the right way and rattling off a bit of Latin. The more clearly a wizard understood and visualised their magic, the more they could shape it. He had demonstrated that with Lumos, showing how intent alone could alter its brightness, colour, or even direction. In his first few weeks, he had taken the same approach with Incendio.

And everyone in the room had to admit, grudgingly, in some cases, that they had seen a sharp increase in students' mastery over the spell.

McGonagall tapped her fingers on the desk. "I had fourth-years in Transfiguration applying your method to their own spellwork. It seems your lessons have encouraged them to think beyond rote memorisation."

Flitwick nodded. "A rather commendable result. If students truly understand the magic they wield, they are less likely to misuse it."

Snape, predictably, looked unimpressed. "Or perhaps you are encouraging a generation of children to play with fire… and we will be the ones cleaning up the ashes."

Cassian leaned back. "If they understand what they are doing, they won't have to rely on waving their wands around hoping for the best. I would argue that is safer than the alternative. Better they burn their fingers in here than set the world alight because no one taught them properly."

Snape gave him a look but didn't argue. The discussion moved on to other matters… disciplinary concerns, upcoming events, and the usual bureaucratic nonsense Cassian had little interest in. When it was finally over, he left the office without bothering to glance at Snape, who looked as though he had just swallowed a lemon.

***

The next day, Cassian's class was with the fifth-year Slytherins and Ravenclaws. At the front of the room, his cousin, Selena Rosier, sat with the same innate grace she always carried. Unlike most of their family, Selena wasn't an idiot. She actually had a brain and used it. Their relationship had never been particularly close, but she didn't look at him like he was a complete waste of air, which, considering the Rosier name, was saying something.

Cassian waved his wand, and a globe hovered in the air, its surface shifting until it showed a single, unfamiliar continent. Cassian leaned back against his desk, arms crossed.

"How many of you know how the world was created?" he asked.

Silence. A few glances were exchanged. Some students looked suspicious.

A Ravenclaw, Lenny Pindlebrook, spoke first. "Mythologically or magically?"

"Either. Both." Cassian flicked his wand, and the globe shifted again, this time splitting into several landmasses. "Every culture has its stories… gods sculpting mountains from chaos, cosmic eggs cracking open, titans bleeding oceans into existence. Wizards are no different… we just like to pretend our versions are smarter."

He gestured, and the image morphed, displaying crude cave drawings, early depictions of magic. "And then there is magic itself. No one really knows where it started. Some believe it's always been here, woven into the fabric of the world. Others think it came later, a gift, or a curse, bestowed by something greater."

A Muggle-born girl hesitated before raising her hand. "Um, Muggles believe Earth used to be part of the sun."

Cassian glanced at her. "Go on."

She shifted in her seat. "Well, the solar system formed from this massive cloud of gas and dust. Gravity pulled everything together, and the sun ignited first. The planets, including Earth, came from the leftover material. Over millions of years, Earth cooled down, oceans formed, life began… then evolution took over."

Cassian nodded. "Not far off from some wizarding theories. The magical community doesn't dispute the physical formation of the planet… rocks are rocks whether you use a wand or not. But where we differ is what happened after." He flicked his wand, and the floating globe shifted, its continents rearranging. "Most wizards believe that magic was always here, woven into the planet itself in the form of ley lines, natural channels of magical energy."

The globe changed again, showing a supercontinent. "This is Pangea. Millions of years ago, all land on Earth was one massive piece. It eventually broke apart, forming the continents we know today. Early magical beings existed long before humans, shaping the land with abilities that modern wizards can only theorise about." The illusion dissolved, and Cassian started to walk between the rows. "Evolution was also part of it. The first magical humans didn't just appear out of nowhere. There is evidence that ancient magical communities developed separately from Muggle ones, different lineages, different adaptations."

A Slytherin boy frowned. "Then why are there Muggle-borns?"

Cassian shrugged. "No one knows for certain. Magic doesn't follow strict hereditary rules. Some believe it skips generations. Others think it is an ancient bloodline trait that reawakens. Then there is the theory that magic itself chooses people. Either way, magic doesn't care about bloodlines… no matter how loudly Purebloods wish it did." He let that settle before continuing. "Now, history. Who can tell me the earliest recorded magical civilisation?"

Selena Rosier, raised her hand. "The Sumerians."

Cassian nodded. "Correct. The Sumerians were among the first to document magic in writing. Their clay tablets detail rituals, spells, and magical laws… some of which evolved into modern incantations." He gestured, and glowing symbols floated in the air. "These are proto-runes, early attempts at codifying magic. Before wands, before structured spellwork, witches and wizards relied on runes, spoken incantations, and raw willpower."

Lenny Pindlebrook, raised a hand. "What about Egyptian magic?"

Cassian flicked his wand again. The symbols shifted into hieroglyphs. "Ancient Egypt took magical practice to another level. Their spells were so tightly woven into daily life that it was impossible to separate magic from religion, governance, or even medicine. Wards, protective enchantments, preservation magic… they pioneered it."

A Slytherin girl muttered, "And grave curses."

Cassian smirked. "Oh, plenty of those. Egyptian curse magic was exceptionally advanced, layered with intent-based spells that didn't just activate when disturbed, but actively sought out trespassers. That is why tomb raiding is such a spectacularly bad idea… though some still insist on testing their luck."

A few chuckles. Leander Rosier's 'aspiring Curse-Breaker' ambitions were well known in the castle. To hear his cousin say this, well, gossip was bound to spread.

Cassian let the discussion continue, nudging students to consider how early magical societies influenced modern spellcasting. Eventually, he brought them back to the present topic.

"Now, onto something practical." He tapped the board, and the words Softening Charm (Spongify) appeared. "This spell was historically used for cushioning falls, making terrain easier to traverse, and even altering the consistency of objects for various purposes."

A Ravenclaw scoffed. "Sounds useless."

Cassian raised a brow. "Does it?"

The Ravenclaw, clearly unimpressed, shrugged. "I mean, bouncing off the ground doesn't seem that useful compared to, I don't know, actual spells that do something."

"Try falling fifty feet off a broom, then tell me Spongify's useless," Selena drawled without looking up.

Cassian smirked. "Exactly. Funny how the simplest spells suddenly matter when you are plummeting face-first into the ground." He tapped his wand against the board, and the words shifted, highlighting different uses throughout history.

Cassian looked at the class. "The first recorded use of this spell dates back to the Sumerians. They are believed to have used it in construction and spell carving."

(Check Here)

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"Tell me, class,

What separates a ghost from the living?"

You raise your hand timidly.

"They… don't interact with the world?

"Exactly," Cassian purrs.

"Like you. Floating silently through my chapters. Incorporeal. Weightless.

Dead to me."