Arcturus Black I

Arcturus Black (1835-1893) was a pure-blood wizard. He was an early member of the House of Black, and it is possible that he was the brother of Cygnus and mrs. Blishwick, and uncle of Phineas Nigellus and his siblings (Sirius, Elladora, and Isla).

Etymology
Arcturus is a name of star. There were another Blacks with the name Arcturus, such as Arcturus Black II and Arcturus Black III.

Behind the scenes

 * Based on a statement by Horace Slughorn, Arcturus may have graduated at Hogwarts and was sorted into Slytherin house.However, he attended Hogwarts c. 1846 - 1853, whem Slughorn wasn´t Potions teacher.
 * This character appears only on the version of the Black family tree shown in the film adaptation of Harry Potter and the Order of the Phoenix. He was not included on the version of the tree which J. K. Rowling gave to a charity auction in 2006. However, according to director David Yates, Rowling provided the filmmakers with a copy of the Black family tree going back eight generations. The filmmakers presumably received a more complete version of the tree than the one auctioned off, which only goes back six generations.
 * Cygnus Black I was possibly his older brother. It's possible that Arcturus' great nephew is named after him.