Summons a large protective barrier
Bodies crossing the boundaries of the barrier disintegrate on the spot, while spells cast at it (if not of enough power to break it) create large, resonating explosions. This spell is the core of the shield summoned around Hogwarts; it is the shield itself that is seen descending over the castle. It should be noted however that on occasion protective enchantments can be breached with a the shield penetration spell.
- This spell was cast by Headmaster Albus Dumbledore to protect the boundaries of Hogwarts Castle from the Death Eater forces in the early hours of 1 September, 1996. Indeed a Death Eater tried to cross the barrier on a broom but was repelled by the shield.
- This spell was cast by Charms Master Filius Flitwick to protect the boundaries of Hogwarts Castle from the Death Eater forces in the late hours of 1 May, 1998, prior to the Battle of Hogwarts that started at midnight the next day. The Death Eaters, on Voldemort's command, started bombarding the magical protection with spells, and it was ultimately brought down by a spell cast by Voldemort.
- The incantation is derived from the Latin "protego", meaning "I defend", or "I protect", and "maxima", nominative feminine singular of "maximus", meaning "greatest", or "highest limit"; altogether the incantation means "I protect to the highest limit".
Behind the scenes
- In the novel, Flitwick uses Protego Horribilis instead when casting the defensive enchantments around Hogwarts.
- In Harry Potter and the Deathly Hallows, the protective enchantments around the grounds were summoned by Filius Flitwick, and Flitwick alone. In the second part of the film adaptation, Flitwick is joined by Molly Weasley, Horace Slughorn, and Poppy Pomfrey to do so.
- In LEGO Harry Potter: Years 5-7 the protective enchantments around the ground are summoned by Filius Flitwick, Horace Slughorn and Minerva McGonagall. Molly Weasley does not help the teachers to do it.
- In LEGO Harry Potter: Years 5-7, a shield was cast over 4 Privet Drive (possibly by Alastor Moody).
- Harry Potter and the Half-Blood Prince (film) (First appearance)
- Harry Potter and the Deathly Hallows (Indirect mention)
- Harry Potter and the Deathly Hallows: Part 2 (First identified as Protego Maxima)
- Harry Potter and the Deathly Hallows: Part 2 (video game)
- LEGO Harry Potter: Years 5-7