A great biographical dictionary of the scholars of Baghdad, prefaced by a topography of the city that gathers earlier reports about the Round City: its measurements in cubits, the construction of its walls, the gates and their domed chambers, the palace of the Green Dome and the mosque.
Al-Khatib al-Baghdadi (1002–1071) compiled the lives of some eight thousand men of learning connected with Baghdad. His introduction describes the city itself, quoting earlier authorities by name. It is the fullest source for the dimensions of the Round City: the thickness and height of the walls, the number of towers between the gates, the size of the palace and the mosque, and the height of the Green Dome, crowned by the figure of a horseman, which was said to fall in a storm in 941.
Many of the figures are given in cubits and depend on which cubit is meant, and some are contradictory; every modern reconstruction of the Round City is an interpretation of this text and al-Ya‘qubi’s.
The book, part by part
I The Round City
Foundation by al-Mansur; the plan; walls, towers, moat and gates; the palace, the Green Dome and the mosque.
Rules: The round city: every quarter equally near the ruler · Moat, two walls and bent gates · The centre kept empty for palace and mosque