The Sorting Ceremony is an annual tradition that takes place at the beginning of every school year at Hogwarts. It is held in the Great Hall before the start-of-term feast. The new first-year students are led into the Hall after the rest of the student body and staff have taken their seats at the four long House tables. At the head of the Hall, before the staff table, a three-legged stool is placed. Professor Minerva McGonagall, in her capacity as Deputy Headmistress, traditionally places the ancient Sorting Hat upon this stool. The Hat appears tattered, patched, and frayed. The ceremony begins when the rip near the brim of the Hat opens like a mouth and it sings a song. After the song, Professor McGonagall reads the names of the first-years from a long roll of parchment.
The core purpose of the Sorting Ceremony is to assign each new student to one of the four Hogwarts Houses: Gryffindor, Hufflepuff, Ravenclaw, or Slytherin.
Once the decision is made, the Hat loudly proclaims the name of the chosen House. The student then removes the Hat, and their new House table erupts in applause as they go to join their housemates. The ceremony concludes once the last student has been sorted.
The Sorting Ceremony was devised by the four founders of Hogwarts a thousand years ago. Concerned about how students would be sorted into their respective houses after their deaths, Godric Gryffindor provided his own hat. All four founders imbued it with their intelligence and criteria, creating the sentient Sorting Hat to carry on the task for them. The ceremony has been the first official act for every incoming student at Hogwarts ever since, marking their formal induction into the school.
The Sorting Ceremony is a significant recurring event in the series.