The Arab Agricultural Revolution was the transformation in agriculture from the 8th to the 13th century in the Islamic region of the Old World. The agronomic literature of the time, with major books by Ibn Bassal and Abū l-Khayr al-Ishbīlī, demonstrates the extensive diffusion of useful plants to Medieval Spain (al-Andalus), and the growth in Islamic scientific knowledge of agriculture and horticulture. Medieval Arab historians and geographers described al-Andalus as a fertile and prosperous region with abundant water, full of fruit from trees such as the olive and pomegranate. Archaeological evidence demonstrates improvements in animal husbandry and in irrigation such as with the sakia water wheel. These changes made agriculture far more productive, supporting population growth, urbanisat