The report is devoted to the analysis of the materials of two diaries of the Russian diplomat Georgy Antonovich Planson (1859—?). The author uses a microhistorical approach as a methodology, since it can be used to identify prevailing ideas and trends in society at that time as a whole. The author of the article concludes that diplomatic diaries are certa inly of scientific interest. It is obvious from the diaries that among the Russian diplomats, the outcome of the war was known several years befo re it began, as a result, the war was not popular. Of particular scientific interest is the description of the process of forming the composition of the Russian delegation in the United States; persons were recorded who for one reason or another did not become delegates. The diaries also con tain materials on similar topics similar to the diplomatic life of the begin ning of the XX century, and the specifics of maintaining a diplomatic protocol. The novelty of the article lies in the fact that new archival mate rials are introduced into scientific circulation.