The Sorting Hat is a sentient hat at Hogwarts that magically determines which of the four school Houses each new student belongs most to. These four Houses are Gryffindor, Hufflepuff, Ravenclaw, and Slytherin.The Sorting Hat originally belonged to Godric Gryffindor, one of the four founders of Hogwarts. It normally stays in the Headmaster's office until it is needed.
The famous Hogwarts Sorting Hat gives an account of its own genesis in a series of songs.During the opening banquet at the beginning of each school year, the first-year students are lined up and their names read aloud alphabetically. Each then takes a seat on a stool and the hat is placed on his or her head. The hat is battered and old; it's patched, frayed, and extremely dirty. In order to speak and sing, a tear along the brim opens like a mouth. It speaks to the wearer inside of the hat with a small, quiet voice, using Legilimency to interpret their thoughts and respond to them.After a time of consideration, the hat announces its choice aloud for all to hear, and the student joins the selected house. The moment of consideration varies in time period from less than a second to over five minutes (known as "hatstall"). The Sorting Hat is notorious for refusing to admit it has made a mistake in its sorting of a student. On those occasions when Slytherins behave altruistically or selflessly, when Ravenclaws flunk all their exams, when Hufflepuffs prove lazy yet academically gifted, and when Gryffindors exhibit cowardice, the Hat steadfastly backs its original decision. On balance, however, the Hat has made remarkably few errors of judgement over the many centuries it has been at work.
The Patronus Charm (Expecto Patronum) was the most famous and one of the most powerful defensive charms known to wizardkind.It was an immensely complicated and an extremely difficult spell, that evoked a partially-tangible positive energy force known as a Patronus or spirit guardian.It was the primary protection against Dementors and Lethifolds, against which there were no other defence. There are two types of Patronuses: corporeal which means a Patronus with a particular shape and form and incorporeal Patronus. Incorporeal Patronuses have no particular shape and do not protect against dementors the way corporeal Patronuses do. However, some wizards like Remus Lupin choose to cast incorporeal Patronuses to hide their identity.
It is evident from old woodcuts and scrolls that the Patronus Charm has been used since ancient times. Therefore, it is unknown who created it, or when it was first invented.The charm also has a long association with those fighting for lofty or noble causes (those able to produce corporeal Patronuses were often elected to high office within the Wizengamot and Ministry of Magic). According to legend, one of the most famous Patronuses of all time was a lowly mouse, which belonged to a young wizard called Illyius. Illyius cast the Patronus Charm when his village was being attacked by the Dark wizard Raczidian and his army of Dementors. Despite the mouse's diminutive size, it shone with a brilliant light, bringing the Dementors to a halt as it nimbly moved through the ranks of fleeing villagers.Enraged, Raczidian decided to enter the fray himself, and tried to summon a Patronus to ward off Illyius's mouse. However, he failed to remember that only the pure of heart can produce a Patronus and thus, for the first time in history, it was revealed what happens when a competent, but unworthy wizard or witch attempts the spell; maggots shot out of Raczidian's wand and quickly devoured him as they engulfed his entire body. The villagers then hailed Illyius as a hero.