Ancilian Charm

The **Ancilian** **Charm** (*Protego Ultima*) was a charm that protected the caster with an invisible shield that reflected spells and blocked physical entities. It was a variation of the Shield Charm, and was used to stop and repel any intruder and/or spell from the protected area, except the most powerful curses, including the Unforgivable Curses. was a stronger version of the Shield Charm that, when cast in combination with *Fianto Duri* and *Repello Inimicum*, conjured up an almost impregnable magical protection barrier

was the most famous and one of the most powerful defensive charms known to wizardkind. It was an immensely complicated and extremely difficult spell that channelled the caster's positive emotions into a powerful protection and evoked a partially-tangible positive energy force known as a **Patronus** (pl. **Patronuses**) or **spirit guardian**. It was the primary protection against Dementors and Lethifolds, against which there were no other defences.

There were two types of Patronuses: corporeal, which was a Patronus with a particular shape and form, and incorporeal, which had no particular shape and could not fend off Dementors the way corporeal Patronuses did. However, some wizards like Remus Lupin chose to cast incorporeal Patronuses to hide their identity.

## Description

It was probably the most powerful version of the Shield Charm, which was used as a protective enchantment against anything approaching the protected area, and against any dark magic, except the Killing Curse, which was unblockable with *any* Shield Charm and passed through it, presumably leaving holes into the magical shield. By extended use of a spell, the magical shield could eventually be broken down.

Patronuses took forms that their casters might not expect, for which they had never felt a particular affinity, or (in rare cases) even recognised. Every Patronus was as unique as its creator, and even identical twins had been known to produce very different Patronuses.

Given these animals' long affinity with humans, it is perhaps unsurprising that among the most common Patronuses when cast (although it must be noted that any corporeal Patronus was highly unusual) were dogs, cats, and horses.

The unusual witches and wizards who produced a Patronus that took the form of their favourite animal was an indicator of obsession or eccentricity. Here was a wizard who may not have been able to hide their essential self in common life, and may have paraded tendencies that others might have preferred to conceal. Whatever the form of their Patronus, one would be well-advised to show respect, and occasionally caution, towards a witch or wizard who produced the Patronus of their choice.

## Casting and effects

The Killing Curse was known to be unblockable, as once it struck the living victim, it almost always resulted in immediate death. There was "no counter-curse", since it was impossible to revive the dead. However there were some exceptions:

The most effective method of surviving the Killing Curse was through sacrificial protection; the willing sacrifice of one's life for another, a manifestation of love, which was the most potent defence against the "unblockable" Killing Curse. Love was a powerful and mysterious branch of magic; it gave those who experienced it the ability to do very great things.

People who were out of the shield couldn't see and hear the wizards or witches that were protected. Spells cast at it (if not of enough power to break it) created large, resonating explosions. This spell was the core of the shield summoned around Hogwarts; it was the shield itself that was seen descending over the castle. It should be noted however that on occasion protective enchantments could be breached with a shield penetration spell

The Killing Curse had no counter-curse and couldn't be blocked by most magical means. However, the green energy bolt might be dodged, blocked with solid objects or intercepted with a few other powerful fast spells, particularly the Stunning Spell. For instance, Albus Dumbledore enchanted a statue from the Fountain of Magical Brethren to shield Harry Potter from Voldemort's Killing Curse during the Battle of the Department of Mysteries. If the curse missed the victim and struck an inanimate object instead, it might cause a small explosion at the point of impact results, which might start a fire of green flame. However, the curse might also ricochet off the object in question

To successfully cast the spell, one began by mustering the happiest memory they could think of; the happier the memory, the better the charm would work. Alternatively, one could imagine a scenario that would act as a very happy memory, as Harry did for his D.A.D.A. O.W.L. The next step was to begin drawing circles with their wand so as to increase the power of their spell. They must then say the incantation, *Expecto Patronum*; the Patronus would come from the tip of the wand and could be directed towards a target by pointing one's wand at said target.

The vast majority of witches and wizards were unable to produce any form of Patronus, and to create even an incorporeal one was generally considered a mark of superior magical ability. Rubeus Hagrid was an example of a wizard who could not conjure any form of Patronus, as the charm was too difficult for him. Alternatively, Minerva McGonagall was the only person seen to be able to produce three Patronus charms at once.

It was possible to disguise the form one's Patronus took, which was done both by Severus Snape to hide his love for Lily Evans, and by Remus Lupin, who felt it would give away his condition.

Some witches and wizards may have been unable to produce a Patronus at all until they had undergone some kind of psychic shock.

Although it was extremely hard to fully conjure a Patronus, in an alternate reality, fourth-years in Defence Against the Dark Arts class were tasked with casting this charm

## Etymology

* The incantation comes from Latin "*protego*", "I protect", and "*ultima*", a declension of "*ultimus*", meaning "ultimate, final, the last".
* The charm name is derivded from the legend of the *ancilia*, which were twelve sacred shields kept in the Temple of Mars. According to legend, one divine shield fell from heaven during the reign of Numa Pompilius, the second king of Rome. He ordered eleven copies made to confuse would-be thieves, since the original shield was regarded as one of the *pignora imperii*, sacred guarantors that perpetuated Rome as a sovereign entity.