Roman law is the law that was valid in the city of Rome in ancient time and later in the Roman Empire. After the end of Roman rule in Europe, in modification, it applied and not completely abandoned.
In the Middle Ages (from about the end of the 11th century onwards), people began to revert to the law of the Romans. At first, Roman law was scientifically studied and taught at the universities in Bologna, then it applied, in the field of civil law. This process of the reintroduction of Roman law took place at various times and to varying extents in almost all of Europe except England. For example, from the 16th century, Roman law applied in large parts of Europe. However, the received law was not identical with the Roman law of antiquity: it had been changed in numerous ways during the process of reception and mixed with legal ideas of other origins. Because the law, which was based on the reception and transformation of ancient Roman law, was common to the various states and regions of Europe, it is called Ius Commune or Common Law.
In the form of common law, Roman law applied in Europe until it was replaced by the civil-law codifications of the 18th and 19th centuries. In some areas of Germany, it was until the entry into force of the Civil Code on 1.1.1900.
Law of the Roman Kings-753-510 B.C.E-After Romulus had distinguished the persons of higher rank from those of inferior condition, then he passed laws and apportioned the duties for each to do: the patricians to be priests and magistrates and judges; the plebeians to be farmers, cattle breeders, and artisans of gainful trades. ... He entrusted and gave the plebeians to the patricians by permitting each plebeian ... to choose for his patron the patrician whom he wished ... and by calling this protection patronage.
DECREE OF SENATE ON JUDICIAL PROCESS IN CYRENE: AUGUSTUS 64 BCE-The magistrate shall bring them immediately before the Senate and shall appoint whatever advocate they request to speak on their behalf to the Senate. He shall not act as advocate against his will if by law he is given the right to decline this compulsory public service.
THE INSTITUTES OF GAIUS-FOURTH COMMENTARY: 170 CE-It remains for us to speak of actions. And if we inquire how many kinds of actions there are, the better opinion seems to be that there are but two, real and personal; for those who say that there are four, and include such as arise from solemn agreements, do not perceive that some kinds of actions are subdivided into others.
THE INSTITUTES OF GAIUS-FIRST COMMENTARY: 170 CE-FIRST COMMENTARY- 1 to 200 I. CONCERNING CIVIL AND NATURAL LAW. (1) All peoples who are ruled by laws and customs partly make use of their own laws, and partly have recourse to those which are common to all men;…