Romantic ballet is defined by an era during the early to mid 19th century (the romantic era) in which ballets featured themes that emphasized intense emotion as a source of aesthetic experience. The plots of many romantic ballets revolved around spirit women — sylphs, wilis, and ghosts — who enslaved the hearts and senses of mortal men. The 1827 ballet La Sylphide is widely considered to be the first, and the 1870 ballet Coppélia is considered to be the last work of romantic ballet.