Slytherin wanted to be more select about who came to Hogwarts; he wanted only pure magical families to attend the school not those of Muggle breed. There was an argument about this between Slytherin and Gryffindor and Slytherin decided to leave the school. Slytherin though had built a hidden chamber before he left and he was the only one who knew about it. He sealed the chamber until his true heir came to Hogwarts and could unleash the horrors from within to kill all those unworthy of using magic, the Muggle-borns.

Once the other three had died they left behind a magical quill to see which other students could come to Hogwarts. It detects the birth of a magical child, and writes his or her name down in a large parchment book. Every year Professor McGonagall checks the book, and sends owls to the people who are turning eleven telling them about their magical powers with an invitation for them to come and attend Hogwarts. They also left behind a sorting hat to choose which house these students would go into. To do this they all put parts of their brains with their own qualities into the hat. The hat would put the student into the house that they reflected mostly in character to one of the four founding members.

They built the school to contain many rooms and secret passages. Many have not been found yet, over 1000 years after the school was built. There are also several towers and separate sections for each house. The grounds are massive as well.

They wanted the great hall to be the best room that they created together so they made sure that it certainly was memorable. They enchanted the ceiling to look like the night sky.

They were also very security conscious. They made sure that no one could apparate or disapparte into the school so that they would be able to make sure that every one coming into the school was authorised. They also protected it from the eyes of Muggles, making sure that if any Muggle stumbled upon Hogwarts they would suddenly remember they had to be somewhere else and see a large pile of rubble instead of the school.

Professor Dumbledore:
Headmaster of Hogwarts, he is very powerful. He is famous for defeating the evil wizard Grindelwald in 1945, the discovery of 12 uses for dragon blood, and his work on alchemy with his partner Nicholas Flamel. He used to be the Transfiguration teacher. Considered by many the greatest wizard of modern times.

Madam Hooch:
Flying Instructer, she gives first years their flying lessons. She is usually referee for the Quidditch Matches.

Madam Irma Pince:
Hogwarts Librarian, she is very strict. She'll examine your note from a teacher very thoroughly when you want something from the Restricted Section.

Professor Minerva McGonagall:
Transfiguration Teacher, shows no favortism for her house and is also strict. She is also an animagi. Head of Gryffindor and Deputy Headmistress of Hogwarts. Professor Severus

Professor Snape:
Potions Teacher, always favors the Slytherins. Particularly dislikes Gryffindors. When he was a first year he knew more curses then most of the seventh years. Was a Death Eater but turned into a spy for Dumbledore. Head of Slytherin.

Rubeus Hagrid:
Is not a true wizard since he was expelled in his third year because he was accused by Tom Riddle for a crime he did not commit. Is now the Care of Magical Creatures Teacher and is also the Keeper for the Keys and Grounds at Hogwarts. He is a half-giant but unlike most giants he is very kind. He tends to think what normal people would say are dangerous, cute and lovable. ex. dragons

Professor Binns:
History of Magic Teacher, he is the only teacher that is a ghost. Became a ghost after he fell asleep in front of a staff room fire and got up the next morning to teach. Students tend to fall asleep in his class they are so bored.

Professor Quirrell:
Former Defense Against the Dark Arts Teacher, he is now dead after failing to retrieve the Sorcerer's Stone to make Voldemort immortal. Pretended to be so afraid with stuttering so no one would suspect him.

Professor Gilderoy Lockhart:
Former Defense Against the Dark Arts Teacher, he has lost his memory after doing a Memory Charm on Ron Weasley's broken wand which backfired. Was so arrogant that even the other teachers did not like him.

Professor Remus Lupin:
Former Defense Against the Dark Arts Teacher, resigned after the school found out he was a werewolf. Is considered by far one of the most effective DADA teachers in twenty years. He gave fun and interactive lessons with learning how to defend oneself against Dark Creatures. He taught Harry how to conjure a Patronus.

Professor Alastor Moody:
Former Defense Against the Dark Arts Teacher, he did not actually teach since he was kidnapped and put in his own trunk by Bartemius Crouch Jr. who was working for Voldemort. Crouch has been given the Dementor's Kiss which is worse then death.

Professor Grubbly-Plank:
Temporary Care of Magical Creatures Teacher, she was the substitute for Hagrid after Rita Skeeter published the article about Hagrid being a half-giant. When she taught it was about unicorns until Hagrid came back.

Professor Kettleburn:
Former Care of Magical Creatures Teacher, he retired at the end of the 2nd book to enjoy more time with his remaining limbs.

Madam Poppy Pomfrey:
Nurse at the Hospital Wing, she is very protective about her patients and is always shooing people away from them.

Professor Filius Flitwick:
Charms Teacher, he is pretty good at teaching the students. He has to sit on a stack of books to see above his desk because he is so small.

Professor Sibyll Trelawney:
Divination Teacher, some students treat her with revere expecially Parvati Patil and Lavender Brown. Other students however think what she says is just guesswork. Professor McGonagall treats her predictions as total bull. Hermione didnt even like it. However Dumbledore says 2 of her predictions have been real so far.

Professor Sprout:
Herbology Teacher, she is a dumpy little witch who teaches students how to take care of strange plants and fungi and what there're used for. Head of the Hufflepuff House.

Professor Sinistra:
Astronomy Teacher, has students study the night skies through their telescopes at midnight and learn names of different stars and the movement of planets. Teaches in the North Tower.

Professor Vector:
Arithmancy Teacher, a difficult subject the teacher assigns homework such as making complicated charts. I do not know much about it.

Argus Filch:
Caretaker of Hogwarts, he is a squib. He constantly wages a war with the students and has a cat named Mrs. Norris. Filch somehow appears seconds later if you put one toe out of line in front Mrs. Norris. If you do anything wrong in front of Filch or Mrs. Norris you are apt to get into detention. He seems to miss using torturing tools on disobeying students.

Professor ???:
Whoever it is teaches Muggle Studies. Most people think it's a soft subject but it's useful if you interact with muggles alot since you obviously learn about the non-magical community.

Professor ???:
Whoever it is teaches Ancient Runes. Also a difficult subject. Not much is known about it.