Roman laws acted as the basis for western civilization's laws when they were established during the medieval and early modern periods in Europe. They continue to influence both civil and common laws.
Roman laws acted as a basis for common laws throughout the west during the early modern and medieval periods. For example, they state that no Roman can be condemned for a crime until he can defend himself against his accuser, which is the same basis used for criminal trials. Similarly, they state that the accuser must prove that the criminal committed the crime, and that someone cannot be convicted based on suspicion alone. Such laws acted as a basis for kings establishing royal writs in Europe, which were used to govern the land.
Although few places directly practice Roman law today, the influences still remain. For example, it was the Romans who introduced the practice of writing laws out in the west, and countries continue to offer their citizens the same clarity. Many of the common law principles remain the same, such as the idea that all men are born free and the introduction of contracts to purchasing and hiring processes. In addition, the ideas behind civil laws remain the same, such as states and governments having the right to implement their own legislation.