A compass rose is used to indicate direction and its most important purpose is to indicate north, thereby orienting the map. While there are no strict rules for drawing or constructing them, the most simple is an arrow point north. Generally, the most complex has 32 points which is accomplished by successively dividing the compass circle in half, giving it first 2, then 4, then 8, then 16, and finally 32 points. The points shown fall in their true position; i.e., a 4-point compass would have 90 degrees between each point; an 8-point compass, 45 degrees; etc. The earliest known use of the magnetic compass was in the 12th century. About a hundred years later the compass car, with the compass or wind rose, was added under the swinging needle. The compass rose greatly advanced the art of navigation.