Sorting Hat. The ancient headpiece used to sort new students into their houses

When Hogwarts first began, the four founders Gryffindor, Slytherin, Ravenclaw and Hufflepuff each took and taught those students who displayed certain characteristics prized by each. Gryffindor took the brave, Slytherin the cunning, Ravenclaw the cleverest and Hufflepuff the rest. In order to know in which of the Houses to place new students, the Sorting Hat was made, and it has been sorting students ever since.

The Hat has seen over a millenium of history come and go, in the minds of the children it is called upon to sort. Every year it looks into the minds of the Hogwarts newcomers and places them according to their natures. The Hat has sat on the heads and read the thoughts of every student Hogwarts ever had. Albus Dumbledore, Tom Riddle, Harry's parents and their friends are but a significant few of the minds the Hat has perused.