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"Professor Vector's supposed to be really strict. I'm not sure I want to do Arithmancy."
— A Hogwarts student mentioning Vector[src]

Professor Septima Vector[4] (fl. 19741996) was a witch and Professor of Arithmancy at Hogwarts School of Witchcraft and Wizardry from at least the 1991–1992 school year. She may have also been the Advanced Arithmancy Studies teacher.

Professor Vector was known among students as a "really strict" teacher, so much so that some pupils were unsure whether to take her classes. She was also known for giving her pupils plenty of highly complicated and difficult homework. Her subject was Hermione Granger's favourite subject while she was in school, but one of her roommates did not like it because she found it too difficult.


Early life

Nothing is known about Vector's early life, though she likely attended a wizarding school such as Hogwarts School of Witchcraft and Wizardry and excelled in Arithmancy, and may even have taken Advanced Arithmancy Studies.

Career at Hogwarts

"We are pleased to welcome a new member of staff this year."
— The Head announcing a new teacher's arrival.[src]

At an unknown point in her life, Vector accepted a teaching position at Hogwarts School. She became the Professor of Arithmancy, being given Classroom 7A on the seventh floor of Hogwarts Castle to teach her lessons in, and presumably an office elsewhere on the school grounds. Her relationship with the rest of the staff is unknown, though she was considered very strict and old-fashioned by some of her students, so she may have been like Minerva McGonagall in personality.

Vector sat by Rubeus Hagrid during the Start-of-Term Feast

Another class, called Advanced Arithmancy Studies, was known to be taught at Hogwarts. It is likely that Professor Vector also took this class. The Advanced Arithmancy Studies classroom was located on the first floor of Hogwarts Castle, in the Turris Magnus.

1991-1992 school year

"Hogwarts, Hogwarts, Hoggy Warty Hogwarts, Teach us something please..."
— Professor Vector and the rest of the school singing the Hogwarts school song[src]

Septima sitting next to unknown professors

Professor Vector worked at Hogwarts School of Witchcraft and Wizardry in the early 1990s and was present at the Sorting of Harry Potter and his classmates.[5]

In the 1991 Start-of-Term Feast, she sat next to Keeper of Keys and Grounds, Rubeus Hagrid. She listened attentively to fellow Professor Minerva McGonagall, who was telling the first-years how the Sorting ceremony would proceed. She also witnessed as Harry Potter was sorted into Gryffindor House.[5]

1993-1994 school year

"I heard [Hermione] talking to Professor Vector, that Arithmancy witch, this morning. They were going on about yesterday's lesson, but Hermione can't've been there, because she was with us in Care of Magical Creatures!"
Ron Weasley concerning Hermione Granger's impossible timetable.[src]

In 1993, Hermione Granger began studying Arithmancy with Professor Vector and excelled in the class. After one lesson, they had a talk about their lesson the following day, which Ronald Weasley overheard, and was confused, as Hermione had Care of Magical Creatures the day before, and so could not have been in Arithmancy. In reality, she had been using a Time-Turner to get to all her lessons.[6]

1994-1995 school year

Hermione: "Lots of homework? Professor Vector didn't give us any at all."
Ron: "Well, bully for Professor Vector."
Hermione Granger and Ron Weasley in 1994.[src]

On 2nd September, 1994, the first day of classes of the 1994-1995 school year, Professor Vector did not give her fourth year students any homework, an unusual occurrence, which Hermione Granger mentioned after Ronald Weasley told her that he had had a lot of homework.[7] She was also presumably present for the arrival of the Triwizard Tournament participants, the Yule Ball and the memorial feast for Cedric Diggory at the end of the year.[8]

1995–1996 school year

" [Hagrid] waved a hand and narrowly missed concussing a frightened-looking Professor Vector, who was passing."
— Professor Vector leaving the Great Hall one morning.[src]

Professor Vector was once again teaching at Hogwarts in 1995, where she was present at the Start-of-Term Feast. When the new DADA teacher, Dolores Umbridge, rudely interrupted Dumbledore to give a speech, Professor Vector and her colleagues were stunned at her audacity. Like her student Hermione Granger, Professor Vector and the other teachers understood the true gravity of the speech (the Ministry was interfering at Hogwarts) and did not clap when Umbridge finished her speech. Professor Umbridge was later appointed High Inquisitor with powers to inspect and dismiss teachers she felt were not up to scratch (or rather, those that were loyal to Dumbledore). Professor Vector's classes were presumably inspected, but she likely proved to be a competent teacher as she was not dismissed or put on probation.[9]

When Rubeus Hagrid returned from a mission given to him by Headmaster Dumbledore, he had a conversation with Harry Potter, Ron Weasley, and Hermione Granger, Professor Vector walked past them and was almost knocked off her feet by Hagrid. As she was passing them and they were entering the Entrance Hall, she had presumably come downstairs to the Great Hall to eat.[10]

Also that year, one boy told someone that he was unsure if he wanted to do Arithmancy because of Professor Vector's strict demeanour[11].

Later in the year, Umbridge became Headmistress after Dumbledore was ousted from Hogwarts, but Professor Vector and her fellow staff members did nothing to help her and instead found means of annoying or hindering her. Indeed, when fireworks went berserk all over the place and a corridor was turned into a swamp (both times courtesy of the Weasley twins), Professor Vector did not attempt to remove either obstacle and took great pleasure in having the Headmistress run all over the castle getting rid of escaped fireworks in the classrooms. When Hogwarts was restored to normalcy and Umbridge was ousted and pursued from the premises by Peeves, Professor Vector and the other teachers did nothing to halt the students from chasing after her.[9]

1996-1997 school year

"Hermione [...] dashed off to see Professor Vector about a mistake she thought she might have made in her last Arithmancy essay."
— Professor Vector being visited by Hermione Granger in May.[src]

In 1996, Hermione Granger thought she may have made a mistake in her homework and visited Professor Vector to discuss it.[12]

Later life

It is likely that Professor Vector participated in the Battle of Hogwarts in May, 1998. Her later life is unknown. If she did participate in the Battle, she presumably survived, as her name was not given among the Fallen Fifty.

Physical appearance

She often wore red robes with a matching pointed hat.[5]

Personality and traits

Professor Vector was described as very strict by a student who was not sure if he should take her lessons.[11] She was also said to have given out masses of complicated homework to her students, who were all third years or over, though appeared to be rather sociable with the other teachers. In addition to her strictness, she was shown to be a competent and skilled teacher, as her lessons passed inspection by Dolores Umbridge; furthermore, she taught Arithmancy for at least six years at Hogwarts, proving her competency and experience as a professor.

Magical abilities and skills

  • Arithmancy: Vector was a highly accomplished Arithmancer, teaching the subject for at least six years, showing her expertise in this very difficult and complicated branch of magic.
  • Charms: Professor Vector was capable of conjuring a non-corporeal Patronus,[3] which is a mark of superior magical ability and skill.


Septima most likely comes directly from Latin Septima which translates to "the seventh" (female form). As seven is the most powerful magical number, and Arithmancy deals with the numbers appearing in magic, this name suits the character well. A "vector" is a concept in physics and mathematics, specifying a quantity that has both magnitude and direction, and represented by an arrow.

Behind the scenes

Aurora Sinistra and Septima Vector in the Great Hall in LEGO Harry Potter: Years 1-4

  • Professor Vector was played by actress Hazel Showham[13] in the the film adaptation of Harry Potter and the Philosopher's Stone, appearing as an unnamed background extra. In an instance of additive retroactive continuity, the physical appearance of this extra was later used to depict Vector in LEGO Harry Potter: Years 1-4.
  • In LEGO Harry Potter: Years 1-4, Septima's character token can be found in the Tom Riddle's diary level. This may indicate she already worked at Hogwarts in the 1940s. Other characters' tokens can be found in matching places, i.e. Minerva McGonagall in the Transfiguration classroom; however, there is another possibility that Septima's token location has no particular meaning.
  • Professor Vector's first name only appeared on a list of the Hogwarts professors which was released on J. K. Rowling's website.
  • Originally, she was a male named Septimus and her last name was intended to be Vecta.[14]


The Harry Potter Wiki has 19 images related to Septima Vector.

Professor Vector in LEGO Harry Potter: Years 1-4

Notes and references

Professors: Septima Vector
Known Arithmancers: Sage Bragnam · Lukas Karuzos · Chiara Lobosca's father · Bridget Wenlock
Textbooks: Numerology and Grammatica · New Theory of Numerology
Arithmancy at Hogwarts: Arithmancy (class) · Classroom 7A · Advanced Arithmancy Studies
Hogwarts faculty
Founders Godric Gryffindor | Helga Hufflepuff | Rowena Ravenclaw | Salazar Slytherin
Headteachers Eupraxia Mole | Vulpus | Phyllida Spore | Dexter Fortescue | Edessa Sakndenberg | Amrose Swott | Everard | Vindictus Veridian | Dilys Derwent | Quintin Trimble | Limebert | Phineas Nigellus Black | Walter Aragon | Basil Fronsac | Armando Dippet | Albus Dumbledore | Dolores Umbridge | Severus Snape | Minerva McGonagall | Brian Gagwilde | Elizabeth Burke
Deputy Heads Minerva McGonagall | Amycus Carrow | Alecto Carrow
Heads of House Filius Flitwick | Neville Longbottom | Minerva McGonagall | Horace Slughorn | Severus Snape | Pomona Sprout
Teaching staff Bartholomew | Bathsheda Babbling | Herbert Beery | Cuthbert Binns | Brindlemore | Charity Burbage | Camelia | Alecto Carrow | Amycus Carrow | Bartemius Crouch Junior (disguised as Alastor Moody) | Albus Dumbledore | Eleazar Fig | Firenze | Filius Flitwick | Fortinbras | Jakub Gorski | Rubeus Hagrid | Rolanda Hooch | Arsenius Jigger | Silvanus Kettleburn | Gilderoy Lockhart | Neville Longbottom | Remus Lupin | Mazoni | Minerva McGonagall | Galatea Merrythought | Prendergast | Quirinus Quirrell | Patricia Rakepick | Concordia Rowle | Arif Sikander | Aurora Sinistra | Horace Slughorn | Severus Snape | Pomona Sprout | Swoopstikes | Sybill Trelawney | Dolores Umbridge | Septima Vector | Unidentified Potions professor (16th century) | Unidentified Charms professor (19th century) | Unidentified Herbology professor (19th century) | Unidentified Potions professor (19th century) | 19th-century DADA professor | Unidentified DADA professor (1984–1985) | Unidentified DADA professor (1985–1986) | Unidentified DADA professor (1986–1987) | Unidentified DADA professor (1987–1988) | Unidentified DADA professor (1989–1990) | Unidentified Muggle Studies professor (1990s) | Unidentified DADA professor (1998–?) | Unidentified Potions professor (21st century) | Unidentified Charms professor (?th century)
Hogwarts house-elves Bilm | Boil-ridden house-elf | Deek | Dobby | Filk | Gimkey | Krafty | Kreacher | Pitts | Retch | Vekey | Wigby | Winky
Support staff Rancorous Carpe | Argus Filch | Wilhelmina Grubbly-Plank | Rubeus Hagrid | Rolanda Hooch | Hankerton Humble | Ogg | Irma Pince | Poppy Pomfrey | Apollyon Pringle | Lucinda Thomsonicle-Pocus | Wainscott | Unidentified Healers | Unidentified Flying Instructor (19th century)