He served in the Moscow office of the Holy Synod, then in the archives of the Senate, and old cases. Here he enthusiastically studied the documents; often worked in drevnehranilische Pogodin. He did not and could not be properly archeographic training, and the state archives, are not listed in order, and for the most part are not described, made it difficult to develop and explore the rich archival material. Despite these adverse conditions, Belyaev was able to do a lot for Russian Archeology and archival. He himself was collecting manuscripts and left a valuable collection, stored in the Rumyantsev Museum. When in 1848 the company secretary Russian history and antiquities at Moscow University, and editor of "Readings", Professor Bodyansky, suffered the punishment for publishing a Russian translation of the works of Fletcher, Belyaev was elected secretary and editor of the "Annals", which started to be published instead of the "Readings" on Change of plans drawn up by Belyaev. Despite serious objections (especially Undolskogo), the plan was approved by the company; Belyaev three times elected secretary and managed to publish 25 books "Annals" (1848 - 1857). Since 1852 Belyaev as an adjunct in the department replaced the history of Russian law at Moscow University, NV Kalachova and remained there until his death. Belyaev lot written and published a lot of monuments. Most of his works are purely descriptive; only a few are devoted to the history of law. The largest of the past - his "Lectures on the History of Russian legislation" - was published after his death and composed in his handwritten notebooks are not intended for publication, with the additions of the student notes. And in this course descriptive element prevails over the legal. Belyaev bytopisatel much more than a historian of law. All his works are nationalistic tone; Belyaev itself has always been a faithful member of the Slavophile camp among historians writers. But slavjanofilstvo Belyaeva was by no means whole philosophical conception of the world; it affected only in his ardent love for Moscow and the Moscow-to antiquity; one and the other had not strictly delimited, and so it came down more to Slavophilism velikorossofilstvu. In his research, he usually walked in the footsteps of the more prominent representatives of destinations, first Pogodin, Aksakov later. In debate with writers Westernizing direction, defending ancestral tribal or personal domination beginning in ancient Russia, Belyaev proved predominance of community life, as a special product of the creative spirit of the Slavic. On the banner Belyaeva, as a writer, only it would be better to inscribe words: the struggle for the community, for its Aboriginal and ubiquity. It is impossible not to acknowledge his great contribution to the clarification of this aspect of our everyday stories; but the very concept of the community in a variety of works Belyaeva is extremely uncertain, vague and accepted in different ways, without any distinction in land communities from administrative, even by common ownership, sometimes merging with the concept of all human communication. This uncertainty is often accompanied by a lack of features validity of the provisions; to confirm they do not provide any documentary evidence, or are those which are not directly related to the test position. Faith or belief of the author often has to be replaced for the reader monument certificate. These negative features works Belyaeva redeemed in part the abundance of fresh material to which it is due to the extensive acquaintance with historical data. His main work - doctoral thesis "The peasants in Russia." In close connection with it are his polemical article about the origin of the village community in Russia ( "Russian Conversation", 1856) and the article "The laws and acts that will set out the serfdom in Russia" ( "Archives of historical and practical information," 1859, Vol. 2 ). These were not his work alone theoretical value, but also affected the implementation of the agrarian reform. The second place is occupied by his studies of agrarian relations in the Moscow State in connection with the taxation systems ( "Annals", Vol XI and XII; "Reading" for 1884 - 85 years.), Many dark questions first light. Noteworthy are his investigations on the organization of the military forces of ancient Russia and the Moscow government, for example, "The brigade and zemshchina", "service people", "The Russian army during the reign of Mikhail Fedorovich" and especially "On guard, stanitsa and field service on the Polish Ukraine Moscow state. " Several of his articles devoted to the questions of the origin and relationship of our chronicles. His master`s thesis: "On the inheritance by intestacy laws to ancient Russian law code" is one of his works failed. Because of its reviews especially valuable research concerning Professor Osokina for financial management in the history of ancient Russia. Since 1861 Belyaev undertook extensive work on Russian history, to explain the history of the formation of the Moscow State. To this end, he outlined a plan for the study and treatment of provincial lands, which then became part of the dominions of Moscow. But "Stories of Russian history," only the second book depict the history of Russia by area; the first deals with the entire Russian land until the XIII century .; 2 - 4 books contain the history of Novgorod, Pskov and Polotsk. In this edition of the author`s death stopped. To this period of his literary activity relates and his article: "Zemsky Sobor in Russia." The publication of the monuments Belyaev had no less service in Russian history than his studies. A number of important acts and monuments for the first time it was put into circulation. These include valuable data on the history of the peasants, the publication of the Novgorod scribe books, discharge recordings, materials in the Moscow trial of history, the Lithuanian Statute in three editions, trading books, a few general historical monuments and so on. D. Works and publications Belyaev placed mainly in " readings "and" Annals "in" Moskvityanin "," Russian Conversation "," Day ", in the publications of the Academy of Sciences. Separately issued a "peasants in Russia" (1st ed. 1860, 4th ed. 1903), "Zemsky Sobor in Russia" (1867, 2nd ed. 1902) and "Lectures on the History of Russian legislation" (1 th ed. 1879, 3rd ed. 1901). On the publication of works Belyaeva gravitates some bad luck. The best and most important study, "The peasants in Russia", from edition to edition more and more distorted. Very poorly prepared for publication and "Lectures". Until recently, there was not, and any amended list of works Belyaeva. A very incomplete list compiled Belyaeva student S. Petrovsky; Worse list annexed to the latest edition of the book "The peasants in Russia"; a correct list of PN Mroczek-Drozdowski, but it has gaps. - See Peter S. "Ivan D. Belyaev" (obituary), "Report and speeches at the solemn meeting of the Moscow University, January 12, 1874".