Septima Vector
Biographical information

Before 1974[1]

Also known as

That Arithmancy witch (by Ronald Weasley)

Physical information




Hair colour

Dark brown[2]

Eye colour


Skin colour


Magical characteristics





Hogwarts School of Witchcraft and Wizardry

"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 (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 complicated 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 lifeEdit

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. However, it is just as possible that she was home-schooled by her parents, though it is unknown if you could achieve an Ordinary Wizarding Level unless at a magical institution.

Career at HogwartsEdit

"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 went to Hogwarts School and applied for a teaching position there, unless the Headmaster approached her directly for her skills. Either way, 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.
File:Hagrid and Vector.png

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.

It is possible that Vector began her career in wizarding education during or before the 1940s[4].

1991-1992 school yearEdit

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

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.

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. Professor Vector attended the first Quidditch match of the school term. She seemed to be cheerful after witnessing the victory of Gryffindor.

Around Christmas, she was seen spending time with an unknown Hogwarts employee.

1993-1994 school yearEdit

"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]
File:Albus and Septima.PNG

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.

Also that year, a ginger girl, roommate of Hermione and best friend of Fay Dunbar, took her subject as well. However, unlike her, she found it hard, and confided in Hermione that it was too difficult for her.

1994-1995 school yearEdit

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 September 1st, 1994, the first day 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.


1995-1996 school yearEdit

" [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]

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.

Also that year, one boy told someone that he was unsure if he wanted to do Arithmancy because of Professor Vector's strict demeanour[5].

1996-1997 school yearEdit

"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 had made a mistake in her homework and visited Professor Vector to discuss it.

Later lifeEdit

It is likely that Professor Vector participated in the Battle of Hogwarts in May, 1998. Her later life is unknown.

Physical appearanceEdit


Professor Vector was a witch with long, thin black hair with a fair skin colour.

Personality and traitsEdit

Professor Vector was described as very strict by a student who was not sure if he should take her lessons.[6] 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. It is possible that she either supported the Gryffindor Quidditch team or was simply unbiased, as she was visibly shocked when Harry Potter lost control of his broom, and when Angelina Johnson was "attacked".

Magical abilities and skillsEdit


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 scenesEdit

File:Lego Professeurs Sinistra et Vector.jpg
  • Professor Vector's role in the films is reduced to a background extra in the film adaptation of Harry Potter and the Philosopher's Stone, in which she is played by Hazel Showham.[7]
  • 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.[8]


The Harry Potter Compendium has 0 images related to Septima Vector.
File:Septima Vector.jpg

Notes and referencesEdit

  1. Professor Vector must have been born before 1975 in order to be old enough for a job at Hogwarts (older than 17).
  2. 2.0 2.1 2.2 Harry Potter and the Philosopher's Stone (film)
  3. 3.0 3.1 LEGO Harry Potter: Years 1-4
  4. Her character token in LEGO Harry Potter: Years 1-4 can be found in the Tom Riddle's Diary chapter.
  5. Harry Potter and the Order of the Phoenix (video game)
  6. Harry Potter and the Order of the Phoenix (video game)
  7. Aveleyman - Hazel Showham
  8. HP Lexicon´s transcript of JKR´s notes
Professors: Septima Vector
Known Arithmancers: Bridget Wenlock
Textbooks: Numerology and Grammatica · New Theory of Numerology
Arithmancy at Hogwarts: Arithmancy (class) · Classroom 7A · Advanced Arithmancy Studies

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