The Buchanans were a wizarding family with a long history. By the mid-19th century, they had resided in a village in the Scottish Borders for many generations and were shunned by their Muggle neighbours, who did not know that they were magical. They had a reputation for being extremely large, aggressive, and drinking excessively, which lead the Muggle villagers to conclude that Buchanan children were sent to correctional facilities or institutionalized when they mysteriously disappeared at eleven.
Mr. Buchanan and his wife had a noisy, chaotic home filled with eleven children. Described as a "fierce" and "proud" man, he held strong anti-Squib views, boasting that no Squib had ever been born into the Buchanan line, and asserting that the birth of a Squib meant that a wizarding family was "in decline" and deserved to be "winnowed out." However, he and his wife did not notice when their third-born son, Angus, failed to display signs of magical ability like all of his other siblings.
Angus, being the kindest and largest of the Buchanan children, was well-liked by his brothers and sisters. Mr. Buchanan's children thus went to elaborate lengths to conceal Angus's Squib status from him and his wife. His daughter Flora forged a Hogwarts acceptance letter for her younger brother, and, on 1 September, 1858, the day that eleven-year-old Angus was due to begin his first year at Hogwarts, his son Hamish carried his little brother to Hogwarts Castle on his broomstick.
The ruse was revealed when the Sorting Hat declined to sort Angus. News soon reached Mr. Buchanan and his wife by owl. Humiliated, he refused to allow his son into the house when he finally arrived home on foot, telling him never to show his face again and chasing him away with curses.
After his disownment, Angus made his own way in the Muggle world, eventually coming to play for the Scottish rugby team. Mr. Buchanan forbade his other children from ever seeing Angus again, but, despite this, all ten of them turned out to support their brother at the Scottish team's first international match.
- Pottermore (Mentioned only)