The research is devoted to the problems of law-making treaties and the breadth of their distribution in the East Slavic state formations of the X‒XIV centuries. The need to study the terms vow and oath is related to the peculiarities of their own Old Rus terminology, where the words denoting the vow (swearing, “khrestne ciluvannya»), oath («rota», «khodyty do roty») and treaty (“ryad”, “ryad polojiti”) are used on the meaning of the same phenomena. By swearing an oath on the terms of the treaty. Therefore, all three terms should be used, although in general it is a single phenomenon. The most studied among all law-making treaties of East Slavic state formations of the X‒XIV centuries. there are international treaties that make up a large array of both original texts and their copies, extracts from treaty texts, as well as mentions of such treaties in chronicles. About 200 treaties are known, of which several dozen have remained more or less complete. A separate independent group among international treaties are peace treaties, both because of their content and in the fact that these treaties are almost impossible to divide into international and inter-princely. Another large and fairly well-studied group of law-making treaties are interprincely treaties. The division of groups of international and inter-princely treaties is partly extremely diffi cult, as their individual varieties are almost identical. Exclusively among the inter-princely should include: a) treaties, the rules of which were of all-Rus (or common to the principality) meaning, establishing universally binding rules (common name at the time ‒ «na ustruyeniye mira») and b) treaties, which enshrined the terms of princely rule. Territorially, inter-princely treaties were spread in all areas of East Slavic state formations of the X‒XIV centuries, both during the reign of the Rurikoviches and during the reign of the fi rst Gedeminovichs. It should be noted that international treaties are usually referred to in the sources as treaties (“ryad”), and inter-princely treaties are more based on the oaths that binded their conclusion («khrestne ciluvannya», «rota»). Therefore, in historical science, they received another name ‒ «Khrestociluval’ni gramoty». Two large blocks of treaties are the treaties of princes with their subjects. A distinction should be made between the political treaties of princes and the “viche”, which embodied the opinion of society and was its representative (the so-called treaties of princes with the people) and the treaties of princes with their servants (so-called free servants, “slugi volnyye”) and boyars. The latter category of treaties is a kind of vassal treaty, but they had many diff erences from such an institution in Western Europe. Both types of treaties are usually mentioned in the sources as oaths, although several fulltext records of princes with the “viche” survived, and for treaties with boyars, the sources themselves know that the reason for dismissal of the boyar could be a breach of treaty by the prince. The least studied among the law-making treaties are vassal treaties and treaties of personal dependence, in which the suzerains were free people and aristocrats. Similarly, intra-family and inter-family contracts have been little studied, although their existence is known from sources. In both cases, the limited subject matter is due to the extremely small source base: although more than a thousand birch-bark manuscripts have been found in the last 70 years, the number of private documents found remains insignifi cant. It is concluded that the complex cellular structure of East Slavic society, where each cell was the smallest social unit. In such a society, vertical connections are very weak and horizontal ones are complex. The cells of this cellular structure do not have hard walls and a person can belong to several neighboring cells. The closets themselves are attracted to each other on the basis of contractual relations. It is noted that this model of society has much in common with the so-called Catalan pactism (pactisme). Key words: East Slavic, Kyivan Rus, Old Rus, Medieval Law, Old Rus Law, Treaty, Legal Oath, International treaty, Source of Law, state formations, Legal history.