Number 12 Grimmauld Place

12 Grimmauld Place is said to be the ancestral home of the Black family. This is curious in a couple of respects.

• Why would the notoriously bigoted Blacks want a house owned by someone non-magical in the first place?¹ We are told they think of themselves as some sort of wizarding nobility,² they should desire an old manner house or castle, not a relatively modern town house.
• The house is oddly animated. We do not really know to what extent that is normal for magical homes, but the idea that Walburga's portrait can open curtains, resist those curtains being closed, and refuse commands from the house's owner seems like more than would be tolerated.³

Lots of fan fiction authors have either insisted that James Potter's mother must be Dorea Black, or similarly placed in the family tree to explain how it is possible for Harry to inherit the house. The Harry Potter Wiki has a simpler and better explanation: the English Common Law concept of the Entailed Estate.⁴ If there are no male Blacks living, and the house was entailed to the male line, then the entail is broken and Sirius is free to pass the house on tho whomever he desires in his will. Perhaps the will could be challenged if Sirius had willed the house to someone entirely unrelated, but he is Harry's god-father and thus (were he free to assume the role) legal guardian. In the absence of an immediate family of his own, providing a legacy for his ward and god-child is expected and natural.

More on Walburga's Portrait

Are wizards so short sighted that it never occurred to them to destroy the Portrait in some way, given it cannot be moved?

• It is possibly shielded.⁵
• It is possibly on a load-bearing wall, and so the wall it is on cannot be physically destroyed.⁶
• She may have bound her soul to it in a pseudo-horcruxy way.⁷ This may give it some of the same protections from harm.