HARRY POTTER AND THE ORDER OF THE PHOENIX HOGWARTS THE GREAT HALL NEW. At the beginning of each year, the students gather in the Great Hall to be welcomed by Headmaster Albus Dumbledore, and to either participate in or witness students being Sorted into one of four houses; Gryffindor, Slytherin, Hufflepuff or Ravenclaw. Throughout the year in the Great Hall, students encounter house ghosts, receive messages and packages via Owl Post, and finally learn which house has been awarded the House Cup. Minerva McGonagall (with Wand, Removeable Hat and Tabby Cat). Professor Minerva McGonagall, Head of Gryffindor house, is a staunch ally for Harry, warning him to tread carefully around someone like Dolores Umbridge. Her Animagus form is a tabby cat.