The Peverell Alliance, simply known as the Alliance, was an organisation formed by Harry Potter and Theodore Nott, with the intent of reducing Draco Malfoy's power within the Slytherin house, and Theodore's installation as the "de facto" leader of the Slytherin house members. It was formed during Harry's third year, in the Hogwarts Express. It would soon gain new members and ideals, such as the close cooperation between houses, something which was prevented by the actions and behaviour of certain students such as Draco Malfoy, which increased their motivation for his downfall.