The Mark of the Horse Lord is a historical novel for children written by Rosemary Sutcliff and published in 1965. It won the first Phoenix Award in 1985. It takes place in Roman Britain and tells the tale of a gladiator who becomes involved with the Dal Riada of Earra-GhĂ idheal. Like many Sutcliff novels, the plot is driven by a crisis of leadership, hinging on acceptance of the ultimate responsibility of a sacrificial king.