enforcing laws on the what? You didn't finish your question.
Answer:
Tarrifs
Explanation:
a tax or duty to be paid on a particular class of imports or exports.
The answer I know for sure is Justinian's code.
Justinian Code, was the result of Emperor Justinian's desire that existing Roman law be collected into a simple and clear system of laws, or code.. Tribonian, a legal minister under Justinian, lead a group of scholars in a 14-month effort to codify existing Roman law.
