Outer covering for the foot, usually of leather, with a stiff or thick sole and heel, and generally reaching no higher than the ankle (unlike a boot). Early examples from Mesopotamia were moccasinlike wraparounds of leather; not until the Hellenistic Age did shoes become luxurious. The Romans developed shoes fitted for the left and right feet, and differentiated according to sex and rank. In the 14th–15th century, shoes became extremely long and pointed, the points attaining a length of 18 in. (45 cm) or more. In the 16th century, the toes became extremely broad, like a duck's bill. In the 17th century, shoes had moderately high heels and were often decorated with large rosettes of lace and ribbons, which gave way to gold or silver buckles in the 18th century. The first shoe factory opened in 1760, in Massachusetts, but not until the development of modern machinery in the 19th century were shoes made quickly and inexpensively.