The history of nails can be divided into three distinct periods: hand-wrought (forged) nails, cut nails, and wire nails. Hand-wrought nails were made by a smith, who worked an iron pin tapering to a point, then inserted it into a nail-header and hammered the broad end to create a nail-head. The Romans extensively used nails, and the term "penny" in medieval England referred to the price of a hundred nails. Until around 1800, artisans known as nailers or nailors made nails by hand. The growth of the nail trade in the American colonies was theoretically held back by the prohibition of new slitting mills by the Iron Act. The slitting mill, introduced to England in 1590, simplified the production of nail rods, leading to the mechanization of the nail-making process between 1790 and 1820. These nails, known as cut nails, were produced by cutting iron bars into rods and were patented in the U.S. by Jacob Perkins in 1795 and in England by Joseph Dyer. Nails have a rich history and have evolved significantly over time, representing an important aspect of human craftsmanship and ingenuity.