Without the trusty oxen the many stone buildings, cathedrals and castles, of medieval Europe would never have been possible. The most magnificent medieval monument to this animal is on top of the Laon Cathedral completed in 1230, it has 16 life sized ox statues on its two towers. 
Clip on medieval oxen use in one of the best TV series of all time.
The definitive study of horses and oxen is by the engineer (and later historian) John Langdon (1944-2016), and the now near-legendary book "Horses, Oxen and Technological Innovation: The Use of Draught Animals in English Farming from 1066–1500".
