Alice and Frank Longbottom are the parents of Neville Longbottom. They were both Aurors and members of the original Order of the Phoenix during the First Wizarding War before they were tortured to insanity by Bellatrix, Rodolphus, and Rabastan Lestrange; and Bartemius Crouch Jr.. Their reason for doing this was they believed that the Longbottoms knew the whereabouts of their fallen master, Lord Voldemort.
The Longbottoms were then sent to St. Mungo's Hospital for Magical Maladies and Injuries, where they stayed permanently. The Longbottoms were considered to be extremely famous, and this attack on them was considered to be one of the most atrocious and infamous acts within the war. As such, the Lestranges and Barty Crouch Jr. were sentenced to life in Azkaban.