Longships were a type of ship invented and used by the Norsemen for trade, commerce, exploration, and warfare during the Viking Age. The longship's design evolved over many centuries, beginning in the Stone Age with the invention of the umiak and continuing up until the 6th century with clinker built ships like Nydam and Kvalsund. The longship appeared in its complete form between the 9th and 13th centuries. The character and appearance of these ships have been reflected in Scandinavian boat-building traditions until today. The particular skills and methods employed in making longships are still used worldwide, often with modern adaptations. They were all made out of wood, with cloth sails (woven wool) and had numerous details and carvings on the hull.