Under patria potestas, the Roman father acted as a judge to settle legal issues within the family. When there was a conflict between the families, the fathers negotiated an agreement from everyone. Students who taught Roman law in Bologna (and later in many other places) found that many rules of roman law were better suited to regulating complex economic transactions than the usual rules that applied throughout Europe. For this reason, Roman law, or at least some of its borrowed provisions, began to be reintroduced into legal practice centuries after the end of the Roman Empire. This process was actively supported by many kings and princes who employed university-trained jurists as court advisors and officials, and tried to take advantage of rules such as the famous Princeps legibus solutus est („The ruler is not bound by laws”), a term originally coined by Ulpian, a Roman jurist. Only England and the Nordic countries did not participate in the full reception of Roman law. One reason for this is that by the time Roman law was rediscovered, the English legal system was more advanced than its continental counterparts. Therefore, the practical benefits of Roman law were less obvious to English practitioners than to continental lawyers. As a result, the English common law system developed alongside Roman civil law, with its practitioners trained at the Inns of Court in London, rather than obtaining degrees in canon or civil law from the universities of Oxford or Cambridge. Elements of Romano-canon law were present in England in the ecclesiastical courts and, less directly, through the development of the system of equality. In addition, some concepts of Roman law have found their place in the common law. Especially in the early 19th century, English lawyers and judges were willing to borrow rules and ideas from continental jurists and directly from Roman law. One explanation for the „reception” of Roman law, according to Professor Alan Watson, is related to the concept of „legal borrowing” – „legal transplantation”.
7 If lawyers and courts are looking for a solution and no solution is available in their own system, the thinking lawyer can find a precedent elsewhere. There were also the law professors initially in the prestigious universities of northern Italy, who studied the legal writings of roman times and filled generations of high-ranking lawyers and administrators in accordance with Roman law. This facilitated the gradual assimilation of Roman law with local customary law. About 60 years after the founding of the Roman Republic, disgruntled plebeians demanded a written code of law and legal rights. The plebeians complained that because the laws were not written, government agencies and creditors could easily abuse the people. As the Roman Republic became an empire, its rulers faced the growing challenge of governing an increasingly diverse and distant population. Legal questions and disputes arose not only between Roman citizens, but also with non-citizens who lived or traveled in their territories, to whom the ius civile did not apply. This led to the development of ius gentium („law of nations”), which included how to divide the law that applied to all peoples and was based on the common principles and arguments that civilized societies and humanity share, and ius naturale („natural law”), a category of laws based on the principles shared by all living beings. Humans and animals (e.g. reproductive laws or physical defense against attacks). As the law became more complex, Roman rulers needed a larger group of legal authorities to bring order to the system of legal formulas and decisions. In the second half of the third century BC.
J.-C., a new professional group of legally trained specialists, the jurists, has emerged to meet this demand. Lawyers were not involved in the administration of the law, but focused on interpreting and generating formal opinions about the law. It was the scientific works and writings of generations of great jurists that elevated Roman law to its peak during the first two and a half centuries of our era, called the classical period of Roman law. Although many have argued that England stood out against the „reception” or „revival” of Roman law and maintained its own common law, it is now accepted that the common law (and consequently the law of Ireland) was also significantly influenced by Roman law. An important branch of Roman law became what is now known as jus scriptum (written law) and jus nonscriptum (unwritten law). The term unwritten law referred strictly to customs, while written law literally represented the whole law on the basis of a written source and evidence. There were different types of written laws, the first of which consisted of laws or decrees of one of the general assemblies of the Roman people. They were a source of law only during the Republic. With the foundation of the empire in 31 BC. J.-C. The function of the assemblies was reduced to the formal ratification of the emperor`s wishes.
The most important laws were the Twelve Tables, which were promulgated in 451 BC. This was the first attempt by the Romans to create a code of law to prevent political struggles between classes.