Common law
The common lawso named because it was "common" to all the king's courts across Englandoriginated in the practices of the courts of the English kings in the centuries following the Norman Conquest in 1066. The British Empire spread the English legal system to its historical colonies, many of which retain the common law system today. These "common law systems" are legal systems that give great precedential weight to common law, and to the style of reasoning inherited from the English legal system.
Common Peace
With 'autonomy and freedom' the Greek states at the beginning of the fourth century found a formula for a inclusive peace system which was acceptable to all sides. After 387 BC no peace was possible without it, even if the individual attempts only held for a few years each. However, the principles of the common peace also found their way into league treaties, such as the Second Athenian Sea League and the League of Corinth. A major opportunity for the development of a true Common Peace lay in the fact that the peace idea proved flexible enough to be developed further in this way.