Albus Dumbledore, Minerva McGonagall and Remus Lupin were all given a First Class Order of Merlin (as was Cornelius Fudge, although his was self-appointed which some felt diminished the value of the award).
As part of the Order of Phoenix's new resistance movement, Minerva fought in several battles of both wars, including the Battle of the Astronomy Tower and the Battle of Hogwarts, where she led the resistance against Lord Voldemort.
It is possible that Harry Potter, Ron Weasley, Hermione Granger, and Neville Longbottom were awarded the Order of Merlin later in their lives due to their contributions throughout the Second Wizarding War and their crucial roles in the defeat of Lord Voldemort.
Order of Merlin (First Class) medal: Fudge awarded himself an Order of Merlin, First Class, medal despite his less-than-distinguishable career, which caused much controversy within the magical community. This was possibly forfeited when his disgraceful lack of action against Lord Voldemort's return was exposed.
An Order of Merlin medal was given to Peter Pettigrew's mother by Minister for Magic Millicent Bagnold in 1981, after he was presumed dead in pursuit of Sirius Black III. Although the medal never belonged to Peter himself, the object was passed to Remus Lupin after Joan Pettigrew's death in 1986.
It is possible that he was taught by Salazar Slytherin himself, given the time period Merlin lived in. It is said that Merlin's wand was of English oak (though his grave has never been found, so this cannot be proven).
Merlin is the most powerful wizard recorded in the history of the wizarding world, even more so than Albus Dumbledore and definitely more powerful than Lord Voldemort. Merlin was intelligent and talented, and during his time at Hogwarts, he managed to decipher many of the secrets of the castle.
Albus Dumbledore, Minerva McGonagall and Remus Lupin were all given a First Class Order of Merlin (as was Cornelius Fudge, although his was self-appointed which some felt diminished the value of the award).
Harry describes Umbridge to Sirius Black, saying that she's vile enough to be a Death Eater, despite not being one. Umbridge is also depicted to be a prejudiced person, despising half-breeds and Muggle-born witches and wizards to the point of firing Hagrid due to his half-giant birth status.
One of the most notable recipients of an Order of Merlin is without a doubt Albus Dumbledore. In his case, he receives it not for his efforts in the conflict with Voldemort, but rather, for his defeat of Grindelwald in their duel in 1945.
It is unusual that Merlin, one of the most famous proponents of Muggle rights and tolerance, would be placed in Slytherin, a house strongly associated with anti-Muggle views, although since he was such an ambitious person with all his plans for the Order of Merlin, it is not entirely surprising.
Unsurprisingly, like most of the living and dead British wizards, Merlin studied at Hogwarts. He was born sometime during the Middle Ages. The fact that he was sorted into the Slytherin house proves yet again that Slytherin doesn't host only those who turn out to be evil wizards and witches.
The once shy and awkward Neville Longbottom showed his true bravery during the battle of Hogwarts and eventually became the head of Gryffindor House while also teaching new students Herbology, his favorite subject.
Later in the year, McGonagall duelled with Death Eater Alecto Carrow during the Battle in the Astronomy Tower and later learned of Snape's murder of Dumbledore. McGonagall was initially appointed as Headmistress, but was demoted after Voldemort took control of the school and placed Snape as Headmaster.
Who became headmaster of Hogwarts after McGonagall?
Loyalty. Professor Marazion succeeded Minerva McGonagall in the post of Head of Hogwarts School of Witchcraft and Wizardry. This individual became Headmaster or Headmistress some time between 2008 and 2017 after Minerva McGonagall went into retirement as she was "getting on a bit".
On turning eleven, Umbridge started attending Hogwarts School of Witchcraft and Wizardry. She was Sorted into Slytherin and her head of house was Horace Slughorn.
Apparently, Umbridge's mother was a Muggle and her brother was a Squib – a source of huge embarrassment for the family. Perhaps their abandonment and retreat back into the Muggle world had such a huge impact on Umbridge that it became the catalyst for her Muggleborn-targeted cruelty later on in life.
If you have only seen the films, you might be surprised to hear that it wasn't Cho Chang who betrayed Dumbledore's Army to Professor Umbridge – it was Marietta Edgecombe. A friend of Cho's and a fellow Ravenclaw, Marietta (reluctantly) joined the DA.
In the Harry Potter universe, Merlin was a wizard who lived sometime after the (Hogwarts) founders´ time. He was sorted in Slytherin. And then everything follows as depicted in Arthurian legends.
Some, such as Morgana, appear to be born with a natural aptitude for magic while others, such as Gaius, can learn to utilize it through years of study. Merlin appears to be an anomaly in that he was born with magic and could use it instinctively from birth (The Dragon's Call).
It will come as no shocker from the title of the book, that Hanna is in fact a descendant of Merlin (which also implies she's a descendant of Morgana), and it is prophesied that only a descendant of Merlin can kill Morgana, because of course.
According to records from the wizarding world, he is thought to have been among the most powerful wizards in human history. Merlin attended Hogwarts as a Slytherin and displayed a remarkable command of the magical arts.
It might seem a bit unthinkable to place Disney's version of Merlin above someone like Gandalf, but he is "the world's most powerful wizard." Merlin isn't just blowing smoke when he makes that claim either, for his power isn't driven by something as simple as a wand alone, but rather his own eccentric will.
"Merlin's beard" was a common wizarding expression used to show surprise. There were several coarser variants, including "Merlin's pants", "Merlin's most baggy Y-fronts", (said by Ronald Weasley) and "Merlin's saggy left —" (Arthur Weasley interrupted Ronald Weasley before he could complete this last expression).
