Horace Slughorn
Horace E. F. Slughorn is a character in the Harry Potter series of novels written by J.K. Rowling. He is a teacher at Hogwarts School of Witchcraft and Wizardry and makes his first appearance in the penultimate book of the series, Harry Potter and the Half-Blood Prince.
Background
Prior to the beginning of the series, Horace Slughorn was the long-serving Potions master at Hogwarts and Head of Slytherin House since at least the 1940s. He retired in the 1980s, but returned to both positions, as Potions master at the beginning of Harry's sixth year at Hogwarts and as Slytherin Housemaster at the end of that year.
During his long initial period of employment at Hogwarts, Slughorn taught several of the main characters in the Harry Potter story. Among his pupils were a young Severus Snape and Lily Evans, Harry's mother and one of Slughorn's favourite students, whom he repeatedly praises as "one of the brightest I ever taught...vivacious...charming...cheeky". Significantly, however, an earlier cohort of students included Tom Marvolo Riddle. On one occasion, Riddle questioned Slughorn about Horcruxes, artifacts which could act as vessels for pieces of a person's soul in order to grant immortality. Having learnt of the nature of Horcruxes, Riddle went on to perform the necessary Dark magic to create his own Horcruxes, which contributed to his formidable power in his later reign of terror under his assumed name of Voldemort.
At some point after his retirement and the resurgence of Voldemort described in the novels, Slughorn went into hiding, concealing all knowledge of his whereabouts from both sides in the growing conflict in the Wizarding world. However, by the beginning of the sixth book in the series, Hogwarts headmaster Professor Albus Dumbledore has agreed to move Professor Severus Snape, now himself Potions master, to the post of Defence Against the Dark Arts teacher, and he manages to locate Slughorn to ask him to succeed Snape.
Involvement in the stories
At the beginning of Harry Potter and the Half-Blood Prince, Slughorn returns to his previous position as Potions teacher. He is initially unwilling to return to the school as he has been in hiding from Voldemort, and fakes a disappearance to mislead Dumbledore. He is persuaded when he sees Harry, who has accompanied Dumbledore, and remarks on Harry's likeness to his parents. Slughorn is reminded that, while on the run, he has not been able to take advantage of the very numerous personal and social contacts he has collected through his life thus far. Dumbledore also makes a point of allowing Slughorn to see that he is now wearing Voldemort's ring.
Slughorn demands less stringent entry criteria for Advanced Potions than his predecessor, Professor Snape, lowering the required grade from a perfect O (Outstanding) to an above-average E (Exceeds Expectations). This last-minute change enables Harry to take Potions to NEWT level, but because he had not expected to be allowed to join the course he has none of the necessary materials. Slughorn lends him an old textbook until he can procure his own.
In his first Potions class, Slughorn offers a small amount of Felix Felicis potion, known as "liquid luck", to the student who brews the best cauldron of the Draught of Living Death. He tells the class that he has taken Felix Felicis twice, once at age 24 and once at age 57. It will give the user constant good fortune for a day, but must be used sparingly. Harry wins the potion, with the help of handwritten notes in the borrowed textbook, which is also signed 'property of the Half-Blood Prince'. Harry continues to use the book in classes with great success, causing Slughorn to remark repeatedly that Harry has inherited his mother's abilities at potions.
Dumbledore, who has undertaken to teach Harry about his nemesis Voldemort by the use of a Pensieve or receptacle for memories, has at some point obtained from Slughorn a memory of Riddle's question about Horcruxes. However, when viewed, the memory turns out to be incomplete. Slughorn, ashamed to admit his involvement in telling Riddle about the artefacts, has deliberately obscured parts of the memory - specifically, his response to Riddle's question.
Dumbledore commissions Harry to obtain the full memory from Slughorn. Partly because Harry's eyes remind him of Lily's, partly because Harry has taken a little of the Felix Felicis, and partly because he has been drinking, Slughorn is eventually persuaded to divulge to Harry the unexpurgated memory. Viewed, the memory convinces Dumbledore that his theory that Voldemort has employed six Horcruxes to achieve immortality is correct.
Towards the end of the story, after the death of Dumbledore during the violence at Hogwarts and the flight of Snape, Slughorn resumes the Headship of Slytherin house on the orders of Professor McGonagall, now Acting Headmistress. He advises the new headteacher that Hogwarts should remain open. Readers await the final book in the series to discover whether Slughorn decides to stay at Hogwarts or return to obscurity.
Appearance and Character
When Slughorn is first introduced, he is described as having prominent, pale-gooseberry eyes, a "shiny pate," and an "enormous, silver, walrus-like moustache." He is "enormously fat", but not very tall, reaching only up to Albus Dumbledore's chin. He considers that he is an old man, though he is not as advanced in years as Dumbledore. He suffers from a weak, wheezy chest and rheumatism. Despite his slightly fragile health, he managed to disappear for a year, travelling incognito and occupying one Muggle house after another while their owners were on holiday.
Slughorn displays some of the character traits typical of those in Slytherin House, such as ambition and a thirst for influence: he is very well-connected in the Wizarding world, and delights in being close to high-profile people. He does not harbour an ambition to be famous himself, however: as Dumbledore comments wryly, "He prefers the backseat; there is more room to spread out." Even after his return to Hogwarts, Slughorn is keen to build ever more connections, and makes a habit of hosting regular receptions for students who are famous, related to famous people, or gifted or talented in one way or another. Known as "The Slug Club", this coterie of students is at the core of Slughorn's constant round of dinners, parties and receptions. In this way he also demonstrates that he is prone to show unbridled favouritism, which is evidenced by his treatment of Ron Weasley. He flatly ignores Ron in favour of Harry himself and Hermione Granger, whom Harry has described to Slughorn as "one of the best in [their] year" even though she was born to a Muggle family and lacked prior experience of Magic.
Another of Slughorn's weaknesses is avarice, which Harry exploits by luring him to Hagrid's hut with a promise to grant him access to Acromantula venom, an extremely valuable magic substance.
Slughorn's personality is a moderated version of the "evil Slytherin" stereotype seen prior to the sixth book in such characters as Draco and Lucius Malfoy or Severus Snape. Despite his ambition, he is not a bad person, and is horribly guilt-ridden that he unwittingly aided Voldemort's rise to power, and is not as prejudiced against Muggle-born witches and wizards as most Slytherins.
It is, however, noteworthy that Slughorn is the first Slytherin ever who has not been portrayed in an entirely negative light. He is instead depicted from a neutral standpoint; on his first meeting with Slughorn, Harry is unsure how to assess him, and throughout the book Slughorn shows both positive and negative traits to his personality. Although he is selfish, superficial, snobbish, materialistic and occasionally deceptive, he is also pleasant, mild-tempered, a good and innovative teacher, and he is ultimately loyal to Dumbledore.
Name and Possible influences
His name, which has a generally unpleasant sound in English in keeping with many of the names of Slytherin students and staff, may be derived from "slug" (to drink alcohol) and "horn" (an ancient drinking cup). 'Slughorn' (also spelt 'Slughorne' or 'Sloggorne') is an old Scottish word derived from 'slogan',and applied primarily to a clan motto. Scotland is JK Rowling's country of adoption, and many of her characters (McLaggen, Moody, Scrimgeour, McGonagall) have Scottish names.