Kirov Ballet, one of the two major ballet companies of Russia, the other being the Bolshoi Ballet. In 1991 it was officially renamed the St. Petersburg Maryinsky Ballet; however, on its frequent tours abroad it is still called the Kirov Ballet. Often regarded as the foremost European ballet company, with strict classical traditions of elegance and beauty, the company was originally the Imperial Russian Ballet. In 1889 it moved into the Maryinsky Theater. Under the direction of Marius Petipa the company premiered the Tchaikovsky ballets Sleeping Beauty (1890) and Swan Lake (1895). The company went into decline after the Russian Revolution in 1917, but the great teacher and ballet mistress Agrippina Vaganova (1879–1951) helped preserve its traditions by training the company's principal dancers. Her work became the foundation of ballet instruction in the Soviet Union. In 1935 the company was renamed the Kirov Ballet. During the cold war, the company experienced difficulties as many of its dancers, including Nureyev, Makarova, and Baryshnikov, defected to the West. Since the fall of the Soviet Union, the company has produced, along with its traditional repertoire, ballets by Balanchine and other modern choreographers. Oleg Vinogradov was the artistic director from 1977 to 1997; Valery Gergiev now holds the post.