Le prophète
Waitresses in an 1840s beer hall in Berlin used roller skates to serve customers. Ballet and opera of the late 1840s, such as "Le prophète", featured roller skating. This helped to make roller skating popular for the first time, in 1850s Europe. Technological improvements helped as well, such as rubber wheels in 1859 and four-wheeled turning skates in 1863. The popularity of roller skating has fluctuated greatly since then; it is typically called a "craze" at its high points.