From about.com:

Early 1700s - In Holland, an unknown Dutchman decided to go ice skating in the summer, ice skating was the widespread method used in the Netherlands to travel the numerous frozen canals in winter. The unknown inventor accomplished dry land skating by nailing wooden spools to strips of wood and attaching them to his shoes. 'Skeelers' was the nickname given to the new dry-land skaters.

1760 - A London instrument maker and inventor, Joseph Merlin, attended a masquerade party wearing one of his new inventions, metal-wheeled boots. Joseph desiring to make a grand entrance added the pizzazz of rolling in while playing the violin. Lining the huge ballroom was a very expensive wall-length mirror. The fiddling skater stood no chance and Merlin crashed solidly into the mirrored wall, as his roller skates crashed into society.

1818 - In Berlin, roller skates made a more graceful entrance into society, with the premier of the German ballet Der Maler oder die Wintervergn Ugungen (The Artist or Winter Pleasures). The ballet called for ice-skating but because it was impossible at that time to produce ice on a stage, roller skates substituted.

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