Half-Blood Prince (character)

The Half-Blood Prince is a fictional character in J. K. Rowling's sixth Harry Potter book, Harry Potter and the Half-Blood Prince.

Spoiler warning: Plot and/or ending details follow.

Harry returns to Hogwarts at the start of his 6th year believing that he will
be unable to take the NEWT-level Potions course because he has failed to receive
the O (Outstanding) in his OWLs that is required by the subject's
teacher, Professor Severus Snape. However, he does not realise that Snape has at
long last been given the Defence Against the Dark Arts position. Dumbledore has
persuaded retired potions master and former head of Slytherin house, Horace
Slughorn to return to the school and resume teaching potions. Slughorn retired
before Snape became potions master, some 15 years earlier. He taught potions to
the class which included Harrys parents James and Lily Potter, Harry's godfather
Sirius Black, Remus Lupin and Snape, and in earlier times also taught Tom
Riddle. Professor McGonagall informs Harry that Slughorn is more lenient and
allows students to advance to NEWT class with an E (Exceeds Expectations)
grade. McGonagall also tells Harry that, as he has not purchased the required
items for the NEWT potions course, Professor Slughorn will provide him with the
necessary supplies temporarily.

Slughorn finds old copies of Advanced Potion-Making by
Libatius Borage from the potions storeroom which he lends to Harry and Ron, who
is also unexpectedly able to continue potions. The copy that Slughorn lends
Harry has alterations to the potions written into it. There is also an
inscription in the same handwiting saying that it is the property of the
Half-Blood Prince,
as well as a collection of jinxes and hexes. Harry's performance in Potions
improves greatly when he decides to use the potion modifications, so much so
that Horace Slughorn compliments him for having inherited his mother's
outstanding ability at potions. Harry wins a Felix Felicis potion which Slughorn
offers as a prize to the student who can brew the best potion, when he uses tips
from the book.

Harry notices that the jinxes and hexes contain crossings out and
corrections, which leads him to believe that they were original work created by
the Prince. In particular, the spell Levicorpus
contains many changes and seems to have caused the Prince
some trouble, but Harry succeeds first time when he tries it on Ron. He notices
that the potions tips do not contain such alterations. Harry also feels that the
Prince is a better potions teacher than either Snape or Slughorn.
Slughorn repeatedly tells Harry of Lily's ability at potions, but only comments
on Snape's abilities once, while saying that Harry made a better first attempt
at a potion than any student ever.

The difference between the potions tips and spells might be because the
potions tips were obtained as-is from another source, or alternatively, because
the Prince was better at creating potions tips than
at writing spells and didn't need to amend those notes. It may be that Snape was
not as skilled as Lily, or may mean that Slughorn knew that Harry would not want
to hear if he was. It may also be that the alternative source of tips was Lily;
indeed, it has been stated throughout canon that Snape was employed as Potions
Master only as a temporary post, and that each year he requested the Defence
Against the Dark Arts post from Professor Dumbledore. However, Snape is
acknowledged to be excellent at creating potions, even recognising from the
student's failures what they did wrong. Dumbledore trusts Snape more than any
one to brew him potions, implying that Snape is better at Potions than
Dumbledore.

Harry learns other new and sometimes dangerous spells from the notes,
including Sectumsempra and Muffliato. Hermione becomes suspicious about the
Prince's nature because of these spells and researches the matter in the
school's library. Remus Lupin suggests checking the age of the book and Hermione
uses the publication date, some 50 years earlier, to look for possible owners.
This is earlier than the period when James, Sirius, Remus and Lily went to
school, who Harry had originally suspected might be the
prince. Lupin confirms that neither James nor Sirius was ever known as 'prince'
anything. Hermione first believes that she has discovered the identity of the
Half-Blood Prince to be a girl named Eileen
Prince, who was a Hogwarts student at the right time. She reveals her
findings to Harry, showing him an article from an old copy of the Daily Prophet,
which says that Eileen was once the Captain of the Hogwarts Gobstones Team. The
fifteen-year-old girl in the paper's photograph is described as being thin,
pale, and sullen-looking, with a long face and thick eyebrows.

Remus tells Harry that the spell Levicorpus was popular around the school
during his fifth year, and indeed had been used by Harry's father James. It is
finally confirmed that this spell had been created by Severus Snape.

Hermione looks through marriage and birth announcements in the Daily Prophet.
She now concludes that Snape's mother, Eileen Prince,
married a Muggle named Tobias Snape. That they had a son, Severus, who was
described as knowing more curses and jinxes when he arrived at Hogwarts than
most did when they left. That 'the Half-Blood
Prince' was thus a literal description of Snape himself, with his
half-muggle status and mother's maiden name of
Prince.

A comparison has been drawn with Tom Riddle, who dubbed himself Lord
Voldemort, which is an anagram of his original name.
Prince is also a title, but the expression
half blood is described as an insult in the wizarding world,
particularly amongst Death Eaters or in Slytherin house, and it is not explained
why he might wish to adopt such a name. Harry asked Remus if he recognised the
name from the time when he was in the same class as Snape, Sirius, James and
Lily but he did not. Later, as Harry tries to use Snape's own spells against him
in the heat of battle, Snape confirms to Potter that he is in fact the
Half-Blood Prince. However, it is still
unclear who originally created the name, and the extent to which other people
referred to him as such.