Date: 836 and later
The historian and geographer al-Yaʿqubi (d. 897-98), records the creation of the new city of Samarra by caliph al-Muʿtasim (r. 833-42). Al-Yaʿqubi writes that architects were tasked with choosing the best sites for palaces. His Turkish generals were placed in charge of building the palaces. Al-Muʿtasim also ordered the laying out of plots of land for housing, the Congregational Mosque, markets, roads, and other functions. See also: Engineer; Surveyor; Construction Worker; Mason.
Citation: Ahmad al-Yaʿqubi, Kitāb al-buldān, ed., M. de Goeje (Leiden: Brill, 1892), p. 258. Translated by Arthur Rhuvon Guest in K. A. C. Creswell, Early Muslim Architecture (Oxford: Clarendon Press, 1932-40), II, p. 229.
Also: Milwright, Marcus. Islamic Arts and Crafts: An Anthology (Edinburgh: Edinburgh University Press, 2017), pp. 32-33.