As a vassal house sworn to King's Landing, House Thorne contributed troops to the defense of the city during the Sack of King's Landing. Ser Alliser Thorne was on the walls when the Lannister troops stormed the Red Keep. He was wounded, captured, and later given the choice between taking the black or being executed. He chose the black.
Nothing else is known about the family save their arms - a silver flail on a red background - and the fact that they still exist.
A historial member of the house is Ser Rickard Thorne, a knight of the Kingsguard who served during the reign of King Viserys I and chose to side with King Aegon II during the Dance of the Dragons.