Baghdad was founded in 764 CE. by the Abbasid Caliph Al-Mansur. In the ninth-century, it came to serve as the center of a flourishing, cosmopolitan intellectual culture throughout the Islamic world.
The city of Baghdad formed two vast semi-circles on the right and left banks of the Tigris, twelve miles in diameter. The numerous suburbs, covered with parks, gardens, villas and beautiful promenades, and plentifully supplied with rich bazaars, and finely built mosques and baths, stretched for a considerable distance on both sides of the river. In the days of its prosperity the population of Baghdad and its suburbs amounted to over two millions! The palace of the Caliph stood in the midst of a vast park several hours in circumference which beside a menagerie and aviary comprised an inclosure for wild animals reserved for the chase. The palace grounds were laid out with gardens, and adorned with exquisite taste with plants, flowers, and trees, reservoirs and fountains, surrounded by sculptured figures. On this side of the river stood the palaces of the great nobles. Immense streets, none less than forty cubits wide, traversed the city from one end to the other, dividing it into blocks or quarters, each under the control of an overseer or supervisor, who looked after the cleanliness, sanitation and the comfort of the inhabitants.
The water exits both on the north and the south were like the city gates, guarded night and day by relays of soldiers stationed on the watch towers on both sides of the river. Every household was plentifully supplied with water at all seasons by the numerous aqueducts which intersected the town; and the streets, gardens and parks were regularly swept and watered, and no refuse was allowed to remain within the walls. An immense square in front of the imperial palace was used for reviews, military inspections, tournaments and races; at night the square and the streets were lighted by lamps.
There was also a vast open space where the troops whose barracks lay on the left bank of the river were paraded daily. The long wide estrades at the different gates of the city were used by the citizens for gossip and recreation or for watching the flow of travelers and country folk into the capital. The different nationalities in the capital had each a head officer to represent their interests with the government, and to whom the stranger could appeal for counsel or help...
Both sides of the river were for miles fronted by the palaces, kiosks, gardens and parks of the grandees and nobles, marble steps led down to the water's edge, and the scene on the river was animated by thousands of gondolas, decked with little flags, dancing like sunbeams on the water,
and carrying the pleasure-seeking Baghdad citizens from one part of the city to the other. Along the wide-stretching quays lay whole fleets at anchor, sea and river craft of all kinds, from the Chinese junk to the old Assyrian raft resting on inflated skins.
The mosques of the city were at once vast in size and remarkably beautiful. There were also in Baghdad numerous colleges of learning, hospitals, infirmaries for both sexes, and lunatic asylums...