In his book Four Thousand Years of Urban Growth: An Historical Census Tertius Chandler traces the history of the worlds largest cities, collecting a wealth of population data across time. This visualization, which is based on his data, plots the growth of each city around the time it was the largest in the world. It is a testament to the forces of time that brings and destroys fortunes.
It starts in 500 BC when ancient Babylon was the largest city, soon taken over by the dramatic rise of Alexandria, which became the largest in just a decade after it was founded by Alexander. Mauryan Pataliputra (Patna) was next, ruling over a united India for the first time. It was followed by the capital of the Han dynasty at X’ian (Changan) . Rome remained the largest for about four centuries before it’s fall. Emperor Constantin moved the Roman capital to Constantinople which became the largest, until superseded by Ctesiphon in Persia. Then X’ian took the top spot again, this time under the Tang dynasty. Baghdad, the seat of the caliph, was next eventually reaching a population of over a million. After it’s decline the Spanish-Moroccan city of Cordova retained the top spot until it was sacked in 1013 AD.