<Tr> <Td> Poppy Pomfrey </Td> <Td> Matron </Td> <Td> The Matron and nurse in charge of the hospital wing during the entire series, being on the position for decades . It was mentioned once that she worked at St. Mungo's before transferring to Hogwarts . She has a reputation for strictness, but when faced with Dolores Umbridge's and later the Death Eaters' abuse of the students, she admits that she never even considered resigning, refusing to leave the students when they needed her most . </Td> </Tr> <Tr> <Td> Quirinus Quirrell </Td> <Td> Muggle Studies / Defence Against the Dark Arts </Td> <Td> The Defence Against the Dark Arts teacher in Harry Potter and the Philosopher's Stone (Harry's first year at Hogwarts). He later turns out to be possessed by Voldemort and is dead by the end of the book . </Td> </Tr> <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>

Name the three hogwarts professors that umbridge put on probation