> You could see the Law Merchant throughout Europe as one example

That is not an example of justice in the absence of the state. All the principal trading cities were governed, whether as city states (Venice), as quasi-independent city states within a federated league (Lubeck, Hamburg, and the other Hanseatic States) or as cities within national kingdoms (London, Ipswich and other cities under the English crown). It is an example of states agreeing to standardized laws to attract traders and provide a solid basis for ongoing trade.

From the Merchant of Venice:

The duke cannot deny the course of law.

For the commodity that strangers have

With us in Venice, if it be denied,

Will much impeach the justice of his state.

Since that the trade and profit of the city

Consisteth of all nations.

The presence of common merchant law does not mean the absense of a state.