type of sail-and-oar vessel that predominated in northern European waters for more than 1,500 years and played an important role in history. Ranging from 45 to 75 feet (14 to 23 metres) in length, clinker-built (with overlapped planks), and carrying a single square sail, the longship was exceptionally sturdy in heavy seas. Its ancestor was, doubtless, the dugout, and the longship remained double-ended; fully developed examples have been found dating from 300 BC. It carried the Vikings on their piratical raids of the 9th century and bore Leif Eriksson to America in 1000; it was also used by Dutch, French, English, and German merchants and warriors. Some of the 11th-century versions shown in the Bayeux Tapestry have their masts supported by shrouds, implying that their square sails could be manipulated enough to sail with the wind abeam. The introduction of the stern rudder about 1200 led to the differentiation of bow and stern and the transformation of the longship.