The article is the first one from a series of articles covers development of private law of the European Union. The article has seen the emergence and development phase of private law in general and in particular, private international law of the EU. The article investigate the issues of forming a European law, which is based on the reception of Roman private law and the influence of the church and the local feudal law. There are fundamental political processes, between the secular and ecclesiastical authority, which has had a fundamental influence on the development of private law. Considerable attention is given to activities of glossators apropos of thinking, systematization and adaptation of these three disparate systems of law to the needs of their time.