<Tr> <Td> Aurora Sinistra </Td> <Td> Astronomy </Td> <Td> The Astronomy teacher during the entire series . Sinistra assists Professor Flitwick in moving a petrified Justin Finch - Fletchley to the hospital wing in Chamber of Secrets and is mentioned sporadically throughout the series . </Td> </Tr> <Tr> <Td> Horace Slughorn </Td> <Td> Potions </Td> <Td> A former Potions master and Head of Slytherin for several decades prior to Harry's birth, Slughorn agrees to come out of retirement and return to these functions at the beginning of Half - Blood Prince . He stays in the job after Voldemort's takeover but sides firmly with the Hogwarts staff against him in Deathly Hallows . </Td> </Tr> <Tr> <Td> Severus Snape </Td> <Td> Potions / Headmaster / Defence Against the Dark Arts </Td> <Td> The Potions master from Harry's first to fifth years, head of Slytherin House from Harry's first to sixth years and Defence Against the Dark Arts teacher in Harry Potter and the Half - Blood Prince (Harry's sixth year at Hogwarts). Snape serves as Headmaster in Harry Potter and the Deathly Hallows, having been appointed by the Minister for Magic, Pius Thicknesse (who was controlled by Voldemort) until he is killed by Voldemort in the final chapters of the novel . </Td> </Tr> <Tr> <Td> Pomona Sprout </Td> <Td> Herbology </Td> <Td> The Herbology teacher and Head of Hufflepuff House during the entire series . She held the job for years, and she carried the position after the Battle of Hogwarts, until she retired and was replaced by Neville Longbottom who, by the time of the epilogue, is said to be the Herbology teacher . </Td> </Tr>

Who is the headmaster of hogwarts after dumbledore died