Whose laws did Darius base his own set of laws on?

Darius has not gone down in history as a lawmaker. But Persia during his reign had a system of laws based on Hammurabi's earlier Mesopotamian code, that had "King's laws" that were valid for the whole nation next to local laws and customs.

The only set of laws that Darius ever ordered was a codification of the laws of Egypt. The basis here remained the ancient Egyptian laws and customs themselves that for the most part had never been properly codified.