List of twenty-eight families supposedly having the purest bloodlines. The list appeared in the infamous publication ‘Pure-Blood Directory’ in the 1930s. Some families protested being included in the list, others complained because they were not included. The list is:
- It is widely believed that Cantankerous Nott is the author of the Pure-Blood Directory (Pm)
- The Potter Family is not included in the Sacred 28 because the author of the list judged from their common Muggle name that they came from "tainted blood" (Pm). This is not true, however, since they were descendents of the illustrious Linfred of Stinchcombe, whose son married a Pure-Blood Peverell and inherited the Cloak of Invisibility passed down by Ignotus Peverell from the Tale of the Three Brothers (Pm, TBB/TTB).
- The Weasley Family is included due to their family tree, but they are considered "Blood Traitors" for being pro-Muggle (Pm).
- The Black Family motto is "Toujours Pur" or "Always Pure" and any family member who was a Squib or who married someone considered beneath their standard was disowned and blasted off the family tree tapestry (BFT, OP6).
- The name of Slytherin died out, but his descendents lived on as the Gaunt family, most of whom were Parselmouths (Pm, HBP10).
- The idea of Blood Status had an effect on American Wizardry as well. Isolt Sayre, a descendent through her mother of Salazar Slytherin, was ripped from her home by her Pure-Blood aunt, Gormlaith Gaunt, who killed her parents and raised her in isolation. She eventually stole Gormlaith's wand, which originally belonged to Slytherin himself, and fled on the Mayflower to America, where she founded Ilvermorny School and married a No-Maj. When Gormlaith discovered Isolt's location and the fact she had married a Muggle, she came to Ilvermorny to kill them, but was defeated with the help of a local Pukwudgies (Pm).