 Russian pop music developed from what was known in the Soviet times as "estrada" into full-fledged industry, with some performers gaining wide international recognition, such as t.A.T.u., Nu Virgos and Vitas.In the 18th century, during the era of Russian Enlightenment, the development of Russian literature was boosted by the works of Mikhail Lomonosov and Denis Fonvizin.By the early 19th century a modern national tradition had emerged, producing some of the greatest writers in Russian history.