Ottonian dynasty
Nicholas d 'Oisy, Lord of Avesnes, nicknamed le Beau, was a son of Walter I, Lord of Avesnes and his wife, Ada of Tournai. He was Lord of Avesnes, Leuze and Condé. He built castles in Landrechies and Condé.
Nicholas was married to Matilda de la... Wikipedia
Cadet branches: Brunonids; House of Savoy
Final ruler: Henry II, Holy Roman Emperor
Founded: 9th century: Liudolf, Duke of Saxony