There's no single answer. Most of them did indeed get started organically, but some got started by dukes who were in the city starting business: https://en.wik

There's no single answer. Most of them did indeed get started organically, but some got started by dukes who were in the city starting business: https://en.wikipedia.org/wiki/House_of_Zähringen https://en.wikipedia.org/wiki/House_of_Zähringen Some got started by Roman Emperors: https://en.wikipedia.org/wiki/Augsburg https://en.wikipedia.org/wiki/Augsburg Some got started by a country wanting a new capital: https://en.wikipedia.org/wiki/Brasília https://en.wikipedia.org/wiki/Brasília And some grew organically, but were at some point or other subject to a massive master plan: https://en.wikipedia.org/wiki/Haussmann%27s_renovation_of_Paris https://en.wikipedia.org/wiki/Haussmann%27s_renovation_of_Pa... https://thegreatestgrid.mcny.org https://thegreatestgrid.mcny.org