Hisham bin Khalid bin Yazid al-Azraq هشام بن خالد بن زيد بن مروان الأزرق · The Chapters on Jihad

“The best of horses are those that are deep black, with a blaze on the forehead, white marks on the legs and white nose and upper lip, and with no whiteness on the right foreleg. If not deep-black, then reddish-brown, with these markings.”