The document discusses how the romantic ballets La Sylphide and Giselle revolutionized ballet in the 19th century by introducing elements of romantic poetry and literature. These ballets featured the ballerina Marie Taglioni and helped create a fundamental change in ballet through their portrayal of supernatural themes. Pointe work became important for depicting mystical creatures and spirits, and Taglioni was praised for her ability to achieve grace and a spiritual quality of movement.