late 15th and early 16th century, both the political centre and the predominant dialect in European Russia came to be based in the Grand Duchy of Moscow (Muscovy). A scientific consensus exists that Russian and Ruthenian had definitely become distinct by this time at the latest. The official language in Muscovy, the Tsardom of Russia and the early Russian Empire remained a kind of Church Slavonic until the close of the 18th century, but, despite attempts at standardization, as by Meletius Smotrytsky in 1620, its purity was by then strongly compromised by an incipient secular literature. Vocabulary was borrowed from Polish, and, through it, from German and other Western European languages. At the same time, a number of words of native (according to a general consensus among etymologists of Russian) coinage or adaptation appeared, at times replacing or supplementing the inherited Indo-European/Common Slavonic vocabulary. Much annalistic, hagiographic, and poetic material survives from the early Muscovite period. Nonetheless, a significant amount of philosophic and secular literature is known to have been destroyed after being proclaimed heretical. The material following the election of the Romanov dynasty in 1613 following the Time of Troubles is rather more complete. Modern Russian literature is considered to have begun in the 17th century, with the autobiography of Avvakum and a corpus of chronique scandaleuse short stories from Moscow. Church Slavonic remained the literary language until the Petrine age (1682–1725), when its usage shrank drastically to biblical and liturgical texts. Legal acts and private letters had been, however, already written in pre-Petrine Muscovy in a less formal language, more closely reflecting spoken Russian. The first grammar of the Russian language was written by Vasily Adodurov in the 1740s, and a more influential one by Mikhail Lomonosov in 1755 (Rossijskaja grammatika). Lomonosov argued for the development of three separate styles of written Russian, in which the higher and middle styles (intended for "the more respectable literary genres") were still supposed to heavily draw upon Church Slavonic vocabulary. In the early 19th century, authors such as Karamzin and Pushkin set further literary standards, and by the year 2000, the common form of the Russian language had become a mixture of purely Russian and Church Slavonic elements. Empire (18th–19th centuries) The political reforms of Peter the Great were accompanied by a reform of the alphabet, and achieved their goal of secularization and modernization. Blocks of specialized vocabulary were adopted from