Sirius Black I

Sirius Black I (1845 – 1853) was a pure-blood wizard and a member of the noble House of Black. He is known primarily from his inclusion on the Black Family Tree tapestry located at 12 Grimmauld Place. As the older brother of the future Hogwarts Headmaster Phineas Nigellus Black, he is the first of three individuals in the family to bear the name Sirius. He died in early childhood and therefore plays no active role in the major events of wizarding history.

Sirius Black I was born in 1845. His parentage is not stated in the original novels, but supplementary materials identify his parents as Cygnus Black and Ella Max (Pottermore). He was the eldest sibling of Phineas Nigellus Black, Elladora Black, and Iola Black (Pottermore). According to the dates inscribed below his name on the family tapestry, Sirius died in 1853 at the age of seven or eight. The cause of his early death is unknown. Because he died before reaching the age of eleven, he would not have attended Hogwarts School of Witchcraft and Wizardry or received a formal magical education. His existence is noted by Harry Potter when examining the Black Family Tree with his godfather, Sirius Black III, who is Sirius I's great-great-grand-nephew.

There is no physical description of Sirius Black I in the novels. His likeness on the Black Family Tree tapestry is mentioned but not described in any detail. Due to his death at a young age, nothing is known of his personality.

Having passed away before he could attend Hogwarts, Sirius I is not known to have developed any significant magical abilities or skills. He would not have owned a wand or received formal training in magic.

Sirius Black I is not known to have owned any significant possessions.

Sirius I's identity is defined entirely by his position within the House of Black.

• Family: He was the eldest son of his generation. His younger brother, Phineas Nigellus Black, would go on to become a notable, if unpopular, Headmaster of Hogwarts. His sister, Elladora Black, is remembered for starting the family tradition of beheading house-elves when they became too old to carry tea trays.
• Namesakes: The name “Sirius” was passed down through the family. His grand-nephew was named Sirius Black II, and his great-great-grand-nephew was Sirius Black III, Harry Potter's godfather. This continuation highlights the House of Black's adherence to tradition.

• Sirius: Following a prominent naming tradition within the House of Black, “Sirius” is the name of the brightest star in Earth's night sky, located in the constellation Canis Major. It is often called the “Dog Star,” which coincidentally foreshadows the Animagus form of his descendant, Sirius Black III. Other family members named after stars and constellations include Orion, Regulus, Bellatrix, and Andromeda.
• Black: The surname likely refers to the family's association with the Dark Arts and their somber, aristocratic nature. It could also refer to a physical trait, such as dark hair, which was common among its members.

• Sirius Black I is mentioned only once in the canonical novels, when his name and dates are read from the Black Family Tree in Harry Potter and the Order of the Phoenix.
• Details about his parents (Cygnus Black and Ella Max) and his third sibling (Iola Black) were revealed on a detailed version of the Black Family Tree hand-drawn by J.K. Rowling for a charity auction in 2006. This information was later canonized on the Pottermore (now Wizarding World) website.
• In the film adaptation of Harry Potter and the Order of the Phoenix, the Black Family Tree is shown, but Sirius Black I is not individually pointed out or discussed.