You're probably thinking about the 1215 Magna Carta - which is the thirteenth century.
Jason Taliodoros has written: 'Law and theology in twelfth-century England'
common law
Common Law
assize of clarendone
Through the Renaissance.
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I think you are referring to the body of "Common Law" which is basically a massive accumulation of court judgements, Royal proclamations and ancient traditions which form the under pinning of the Legal system of England.
Magna Carta of 1215
The English law of contract traces back to the industrial revolution and civil law. It was influenced by ancient Greek and Roman thought. Plato gave some thought to the concept and recognized action should be taken if a contract isn't fulfilled.
If "our' laws equals "US" laws, the Constitution and much of the early laws were much influenced by the ideas of the French Enlightenment of the 18th century. So "France" would be the answer here.
colonial law is not law are rules of english law
If you are referring to ancient civilizations, it can be said that the Greeks had the most influence on the structure of the US government, because much of English law comes from them. If you mean a more modern civilization, it would be the British, since much of our justice system derives from English common law, including the things the states rebelled against.