Explanation: David Graeber’s Debt: The First 5000 years has a section talking about this (it’s the one about Islam in the Middle Ages for those interested), but basically Medieval Muslim society collaborated to actively keep the state away from people’s day to day lives, leading to a system where the whole market ran on honor and good vibes. Unsurprisingly, this looked nothing like the world “free market enthusiasts” envision, at least partially because it was impossible without the Islamic ban on usury. Relevant excerpt:

Large-scale merchants were referred to as sahib al-mal,

“owners of capital,” and legal theorists spoke freely about the creation and expansion of capital funds. At the height of the Caliphate, some of these merchants were in possession of millions of dinars and seeking profitable investment. Why did nothing like modern capitalism emerge? I would highlight two factors. First, Islamic merchants appear to have taken their free-market ideology seriously. The marketplace did not fall under the direct supervision of the government; contracts were made between individuals-ideally, “with a handshake and a glance at heaven"-and thus honor and credit became largely indistinguishable. This is inevitable: you can’t have cutthroat competition where there is no one stopping people from literally cutting one another’s throats.

-Debt page 303