Imperius Curse

"Total control. I could make it jump out the window, drown itself, throw itself down one of your throats..."

- Barty Crouch Jr. as Alastor Moody

The Imperius Curse is one of the three Unforgivable Curses. When cast successfully, it places the victim completely under the caster's control, though a person with exceptional strength of will is capable of resisting it. This makes it unique among the unforgivable curses, as it is the only one of them with a known, reliable method of resistance (sacrificial protection does not count, as it protects against all spells from a certain witch or wizard, not the spell itself, regardless of who is casting it). Cursing another human with the Imperius Curse carries a punishment of a life sentence in Azkaban (unless there is sufficient evidence that the caster did so under the influence of the Imperius Curse). The curse's incantation is Imperio.

Creation
The Imperius Curse was invented during the early middle ages, by dark witches or wizards. The curse was created for coercion and brainwashing for slavery services.

"Unforgivable"
"The Cruciatus, Imperius and Avada Kedavra Curses were not made "unforgivable" until 1717."

- Albus Dumbledore

After the Wizards' Council was reformed into the Ministry of Magic tighter restrictions were placed on the use of certain kinds of magic. The Imperius Curse was deemed by the Ministry to be dark magic, and, along with the Cruciatus and Killing curses, were declared "unforgivable" in 1717. The use of any of these three curses on a fellow human being would result in a life sentence in Azkaban.

Legalisation
"Scores of witches and wizards have claimed that they only did You-Know-Who's bidding under the influence of the Imperius Curse. But here's the rub: how do we sort out the liars?"

- Barty Crouch Jr on the Imperius Curse's controversy.

During the First Wizarding War, when Barty Crouch Sr. was in charge of the Department of Magical Law Enforcement, he fought violence with violence, and legalised the three Unforgivable Curses for Aurors against the Death Eaters in order to win the war. This was repealed once the war was over, as it was no longer necessary. It was also at that time that many Death Eaters, such as Lucius Malfoy and Walden Macnair, claimed that they served Lord Voldemort under the Imperius Curse. While their claims were accepted and were pardoned, the Ministry has gone as far as to assign several personnel to determine who is truly under the curse, and who is lying to escape punishment.

In the 1994–1995 school year, Barty Crouch Jr., under the disguise of Alastor Moody, showed these three curses to his fourth year classes on spiders despite the Ministry's disapproval. Later, in fact, he claimed that he has enough permission to perform the Imperius Curse on students in order to teach them how to resist it.

When Lord Voldemort took over the Ministry, the three curses were once again legalised: this time every wizard and witch had the right to use them as they please. In fact, they were practiced in Hogwarts as part of the curriculum of Dark Arts class under the tutelage of Professor Amycus Carrow. After Voldemort's death and the revolutionising of the Ministry under Minister Kingsley Shacklebolt, the three curses were once again forbidden, and many people under its influence felt like they were coming out of trances.

Effects
"It was the most wonderful feeling. Harry felt a floating sensation as every thought and worry in his head was wiped gently away, leaving nothing but a vague, untraceable happiness. He stood there feeling immensely relaxed, only dimly aware of everyone watching him."

- Harry Potter under the Imperius Curse

The victim of an Imperius Curse is placed in a calm, trance-like state in which all feeling of responsibility and anxiety is banished. They may then be directed to do anything the caster wishes, including crimes such as murder, political corruption, embezzlement, and so on. It is unknown if this hypnosis spell can affect physical capabilities, such as forcing a victim a task such as being stronger or casting spells far above their level, although Neville Longbottom was able to perform a series of "quite astonishing gymnastics" under the curse that he would not normally be capable of.

If the Imperius Curse is performed poorly, then the victim would have their mind addled, an example being Muggle Junior Minister Herbert Chorley. It seems the damage is long-lasting, as Chorley was sent to St Mungo's Hospital for Magical Maladies and Injuries to recuperate.

Resisting the Imperius Curse is possible, but requires great strength of will and character. Harry Potter, Barty Crouch Sr. and Barty Crouch Jr. each learned to resist the curse after being subjected to its effects, though the latter two took quite a long time before building the said resistance. Resisting the Imperius Curse is similar to Occlumency, which requires a great amount of willpower.

According to Harry, using the Imperius Curse caused him to experience "a feeling of tingling warmth that seemed to flow from his mind, down the sinews and veins connecting him to the wand and the curse it had just cast." He believed that his curse might not be very strong, however, thus the sensation from casting a more powerful Imperius Curse may be more intense.

It is possible for someone who has been Imperiused to place others under the curse as well. For example, Madam Rosmerta, who had been Imperiused by Draco Malfoy sometime during the 1996–1997 school year, was able to place Katie Bell under the Imperius Curse in an attempt to deliver a cursed necklace to Albus Dumbledore. It is also possible that the Death Eater Yaxley used the Imperiused Pius Thicknesse to place other high-ranking members of the Ministry of Magic under the curse in order to facilitate the overthrow of Rufus Scrimgeour.

History of Use
Death Eaters made use of the curse in both the First and Second Wizarding Wars to force innocent people to do their bidding. For example, Lucius Malfoy used the Imperius Curse to force Broderick Bode and Sturgis Podmore to try to steal a prophecy from the Department of Mysteries in 1996, and Yaxley placed the Imperius Curse on Pius Thicknesse as part of the plan to take over the Ministry of Magic in 1997.

Ironically, many Death Eaters, such as Lucius Malfoy, avoided imprisonment in Azkaban after Voldemort's first defeat in 1981 by claiming that they had been under the Imperius Curse. As such, it became the Ministry's work to determine who was lying, even though many "victims" managed to deceive them.

Harry Potter and Albus Dumbledore speculated that Merope Gaunt may have used the Imperius Curse on Tom Riddle Sr. to force him to marry her, although Dumbledore thought it more likely that she used a Love Potion.

After the final defeat of Voldemort and the Death Eaters in the Battle of Hogwarts, all of the people across the country who had been Imperiused by him or his supporters became themselves again.

Other Known Uses

 * Herbert Chorley, a Muggle Junior Minister, was the victim of a "poorly-performed Imperius Curse." The resulting symptoms included impersonation of a duck in public, which required him to be removed from society temporarily and transferred into St. Mungo's.

Etymology
This curse takes its name from the Latin imperiosus, meaning "commanding, mighty, and powerful", or imperio, which means "to rule".

Maledizione Imperio

Notes and references
Impero Imperius-Fluch Komennuskirous