In medieval Europe, autonomous cities flourished as centers of commerce.
This region once had independent authority as an autonomous city.
自由都市 (free city) is a broader term that can include cities with special privileges or free ports, while 自治都市 specifically emphasizes self-governance and municipal autonomy.
Compound of 自治 (self-government) and 都市 (city). The term is a modern coinage used to describe historical European communes.