When at the beginning of the 10th century Vikings encroached into the Mediterranean Sea, they were greatly surprised that local vessels carried triangled fore-and-aft sails instead of usual square sails. Normans called them Latin sails (as they called countries of South Europe). The name of a fore-and-aft sail's inventor sank into oblivion. It seems that the fore-and-aft sail came from oriental countries with which Mediterranean countries actively traded. This type of sails appeared to be the most useful and comfortable in conditions of navigation among multiple Mediterranean islands and archipelagoes. The fore-and-aft sail gave possibility to maneuver and to move excellently at side winds. Sea navigators at once appreciated the qualities of such a type of sails. The picture shows a coastal vessel (end of the 9th century) with a beveled post and a single mast inclined to the side of a stem. The ship was steered by two steering oars.