Study of diplomatic patterns of medieval royal documents serves a dual purpose. One would be to systematize and enhance our knowledge about this precious type of historical sources in order to facilitate critical appraisal of their usefulness, and the other to help attain a better understanding of the culture of government, that is, the ability of the ruler and the system of government as a whole to recognize different tasks imposed on them by the process of governing a medieval political organism and to deal with these tasks in the form of written documents. Medieval Serbia stands out as a good object for such research not only because that kind of study has never been carried out on its royal documents, but also because it was exposed to the influence of both major European civilizations of that period, Byzantine and Latin, and underwent profound political changes. In this study, diplomatic patterns are examined on three levels, through a process that can be designated as cumulative diplomatic analysis. The first to be examined are patterns of individual diplomatic ingredients – external, internal, and those whose purpose it was to guarantee the documents’ authenticity. Then the focus shifts to the manner in which these ingredients and their variants come together to produce formal patterns of whole documents – charters, letters and more specific patterns within those two groups. Finally, there comes the investigation of links between these formal patterns and the purpose of individual documents in order to establish the presence and degree of mutual identification, as well as the ways in which form adapted to circumstance, thus creating practical “purpose patterns”. In all, the study identified 474 documents of medieval Serbian ruling figures whose authority can be described as royal or quasi-royal, form the grand župans, kings and emperors of the Nemanjic dynasty and the Lazarević and Branković despots to the independent lords of certain larger regions and the exiled rulers of the period after the Turkish conquest in 1459. Analysis of this modest, yet for the most part sufficient body of diplomatic material, consisting of 52% originals, 43% authentic or interpolated copies, and 5% forgeries, demonstrates that there is practically no individual diplomatic ingredient without at least two or three basic variants, while for some it proved impossible to find a single pair of identical formulas in as many as one or two hundred available examples. Variability can be partially attributed to the number of various authors involved (about 40), but also to the language of the documents, as almost a quarter of the material is made up of items originally issued in Latin (14%) and Greek (9%). These items generally follow patterns characteristic of the wider Latin and Greek diplomatic practices, whereas the remaining Serbian material seldom shows the tendency to completely imitate these models, opting instead to use deeply rooted autochthonous variants occasionally “enriched” with certain Greek or Latin traits. As far as it goes, Greek influence is most pronounced in the 14th century, especially after the crowning of King Dušan, the most powerful Nemanjic, as tsar of Serbs and Greeks in 1346, while in the 15th century foreign influence comes overwhelmingly from the Latin world. Regarding formal document patterns, the distinction between charters and letters is clearly visible, with only a few ambivalent examples. Among charters, several formal types can be singled out, falling into two general categories – solemn and plain. The most prominent in the first category is the arengal type, distinguished by the presence of the narrative backbone composed of the arenga, expositio and dispositio, with elements of the protocol inserted into it, and a generally rich and extensive eschatocol attached at its end. This type is well represented among Greek charters (32,5%), while with Serbian ones it constitutes a clear absolute majority (56,5%), its main characteristics in Serbian material being high variability of individual ingredients, but also great consistency and stability of the general pattern, which goes through three centuries without significant change. In addition to the arengal type, solemn charters can be considered to encompass only the type beginning with the expositio, but this is primarily found in Greek material (56,5%), meeting with very modest reception in Serbian production. Plain charters demonstrate a greater tendency towards formalization of individual ingredients and, on the other hand, more dynamic development of the general form. In the Nemanjid period, after a period of early dominance by the type centered around the oath (iuramentum), the major pattern for plain charters is the one beginning with the promulgatio and titular pronoun. However, from the second half of the 14th century, with the appearance of new regional rulers needing to present themselves more clearly, this model is generally supplanted by the one beginning with a proper intitulatio, although usually still followed by a promulgatio. Patterns based on the oath and the promulgation, as well as those beginning with the dispositio or the date, remain present but relegated to supporting roles. This last one is directly borrowed from Latin practice, where it played a respectable second to the dominant intitulatio type. Latin practice is also generally distinguished by the absence of true solemn types, relying instead on external features to achieve a solemn or plain impression. In fact, the main dividing line among Latin items is the one between charters and letters. Letters themselves make up slightly less than 25% of the total number of documents, and are mostly found in Serbian and Latin material. They can broadly be described as moving from an extremely plain pattern to something resembling plain charters, with a formal distinction between letters open and letters closed, although lack of originals does not allow for a more precise definition of this second type within the Serbian material. These formal patterns demonstrate a high level of identification with certain types of purposes. For example, documents concerning donations largely belong to the arengal and, in Greek material, expositional type (84%), with a very clear link between arengal items and donations to ecclesiastical institutions, considered to be the most solemn type of royal act recorded in documents. As opposed to this, donations to the lay nobility are almost equally consistently recorded in the form of plain charters, and the same goes for court verdicts, regardless whether they involve ecclesiastic or lay parties. Interestingly, Serbian material shows international treaties also being recorded in the form akin to plain donation charters, because all surviving items concern relations with foreign factors of lesser international rank, mostly the city of Dubrovnik. Other purpose types – quittances, notifications, credentials, safe conducts, and orders – mostly rely on letters, carefully modified in form and/or contents to suit each task. Certainly the most elaborate such example is seen in the practice dating to the heyday of the Nemanjic state (mid 14th century) whereby quittances were issued in the form of two separate documents – a plain charter to serve as a perpetual instrument of proof and a letter intended as a notification about the performed transaction. The study clearly shows that patterns were present on all three levels. Although never completely consistent, they are most pronounced in the light of the documents’ purpose. This leads to the conclusion that the makers of Serbian medieval royal documents generally had a very good idea on how a documentary record of a certain royal action should look like. Confirmation of that can be found in the names they gave to their documents – for example, zlatopečatno slovo (golden bull) and its synonyms in both Serbian and Greek material refer primarily to arengal and expositional solemn charters, milost (grace) and povelenie (command) to plain charters for lay addressees, knjiga (script) for letters, with especially telling cases when unusual form and content of certan documents is reflected in equally unusual names. It is, however, a whole new issue whether these patterns were based on precisely established – even written – formularies or simply on the power of tradition and the good sense of the document makers. Available information, especially the high variability of individual diplomatic ingredients, speaks in favor of the latter, with true bureaucratic formalism surfacing only occasionally, usually with plain charters and letters. That also opens the issue of possible involvement of addressees in the making of documents and, thereby, the issue of organization of the Serbian royal chancery. Still, there can be no doubt that the makers of Serbian medieval royal documents were aware of differences in the nature of royal actions for which they were expected to provide written record and capable of choosing appropriate diplomatic patterns to adapt those documents to the demands that every action posed. Istraživanje diplomatičkih obrazaca srednjovekovnih vladarskih dokumenata ima dvojaku svrhu – da sistematizuje i produbi znanja o ovoj dragocenoj vrsti istorijskih izvora kako bi se olakšalo kritičko ocenjivanje njihove saznajne vrednosti i da pomogne da se dođe do bolje predstave o kulturi vlasti, to jest, sposobnosti vladara i upravnog sistema u celini da prepoznaju i u pismenom obliku odgovore na zadatke koje je pred njih postavljalo vođenje jednog srednjovekovnog državnog organizma. Primer srednjovekovne Srbije preporučuje se kao predmet jednog takvog istraživanja već time što u srpskoj nauci ono nikada nije sprovedeno, ali i osobenostima srpskog srednjovekovnog političkog prostora koji se razvijao pod uticajem obe velike evropske civilizacije tog doba, vizantijske i latinske, i prolazio kroz duboke promene. Obrasci su