

Over a thousand years ago, the four greatest witches and wizards of the age shared a dream, to create a school where young people of the wizarding world could study and be trained in the magical arts they needed to become skilled, fully-trained wizards. These four great wizards each founded one of the Houses of the school that they worked together to form: Hogwarts School of Witchcraft and Wizardry. They have been referred to as ‘The Hogwarts Four.’
For a number of years, this arrangement worked just fine. Each of the founders took a group of students to be in their own house and even though they had differences of opinion about who should be trained, the house system helped them all to work together. However, as the years went by, the differences between Gryffindor and Slytherin became a serious rift. Eventually Slytherin left the school.
The four Houses:

Gryffindor is well known for bravery, daring, nerve, and chivalry. The house colours are scarlet and gold, and the house is symbolised by a lion. The entrance to the common room is on the seventh floor hidden behind a portrait of the Fat Lady. In order to get in to the common room Gryffindor students must say the right password.
Founded by: Godric Gryffindor
House Ghost: Sir Nicholas de Mimsy-Porpington (also know as Nearly Headless Nick)
Notable Students: Harry Potter, Ron Weasley, Hermione Granger, Albus Dumbledore, Minerva McGonagall, Rubeus Hagrid, James Potter, Lily Evans, Sirius Black, Remus Lupin, Peter Pettigrew, Ginny Weasley, Neville Longbottom, Fred and George Weasley, Bill Weasley, Charlie Weasley, Percy Weasley, Lavender Brown, Parvati Patil, Seamus Finnigan, Dean Thomas, and Lee Jordan

Hufflepuff is well known for loyalty, fair play, honesty, and tolerance. The house is symbolised by a badger, and the house colours are yellow and black. Its common room is near the kitchens.
Founder: Helga Hufflepuff
House Ghost: Fat Friar
Notable Students: Nymphadora Tonks, Pomona Sprout, Cedric Diggory, Justin Finch-Fletchley, Zacharias Smith, Hannah Abbott, and Ernie Macmillan

Ravenclaw values wit, creativity, and wisdom. The house is symbolised by an eagle and the house colours are blue and bronze. However the house colours are portrayed as blue and silver in the movies with a raven symbolizing the house, and the interior of the house room is decorated with blue and gold. The Ravenclaw common room is located on a high tower. To enter, rather than give a password, one must answer a riddle from an eagle door knocker, such as “Where do vanished objects go?” or “Which came first, the Phoenix or the flame?”
Founder: Rowena Ravenclaw
House Ghost: Helena Ravenclaw (also known as the Grey Lady)
Notable Students: Luna Lovegood, Moaning Myrtle, Cho Chang, Roger Davies, Michael Corner, Padma Patil, Terry Boot, and Filius Flitwick

Slytherin values ambition, cleverness, cunning, resourcefulness, and pure blood heritage. The house is symbolised by a serpent, and the house colours are green and silver. Its common room is in the dungeons through three stones. The password for the 1992-1993 ”Pureblood”. Many people believe students sorted into this house often get involved in the Dark Arts.
Founder: Salazar Slytherin
House Ghost: The Bloody Baron
Notable Students: Tom Riddle, Draco Malfoy, Lucius Malfoy, Bellatrix Lestrange, Vincent Crabbe, Gregory Goyle, Theodore Nott, Narcissa Malfoy, Andromeda Tonks, Regulus Black, Horace Slughorn, and Severus Snape
Students are assigned to a house in their first years during the Sorting Ceremony.