Russkaya Pravda
Having retired from active service, the elderly statesman dedicated himself to scholarly pursuits. Feeling that the Russian historiography had been neglected, he discovered and published several legal monuments of great interest, e.g., Russkaya Pravda and Sudebnik of 1550. His magnum opus was the first sketch of Russian history, entitled "Russian History Dating Back to the Most Ancient Times" and published in 5 volumes after his death. He also compiled the first encyclopedic dictionary of the Russian language.