Sir Henry Bessemer (1813–1898) was an English inventor, known for a process for the manufacture of steel, called the Bessemer process. Before the mid-19th century, steel was made only in small quantities and used only for small items such as swords, tools and cutlery. All large metal structures were made of cast or wrought iron. Bessemer's invention, patented in 1855, was of great importance because it significantly lowered the cost of producing steel. Now steel could be used in the construction of large structures instead of the weaker cast or wrought iron.

In the Bessemer process, molten pig iron was converted to steel by blowing oxygen through it after it was removed from the furnace. This took place inside a large vessel called a Bessemer Converter. This oxidation process burned impurities, chiefly carbon, manganese and silicon, out of the pig iron, creating steel. Bessemer set up his own steelworks in Sheffield and began to manufacture steel at a significantly cheaper price than his rivals.