The mast of a sailing ship is a tall, vertical, or near vertical, spar, or arrangement of spars, which supports the sails. Large ships have several masts, with the size and configuration depending on the style of ship. Until the 20th century, ships' masts were wooden. Originally, they were formed from single piece of timber, typically the trunks of fir trees. From the 16th century, ships were often built of a size requiring masts taller and thicker than could be made from single tree trunks. On… (More on Main-mast)