in 1867 thyssen and several members of his family founded the iron works "thyssen-foussol & co" in duisburg. when this company was dissolved in 1870, he used the new capital to establish with his father the "walzwerk thyssen & co" that would become the base of an industrial empire in the industrialized mülheim an der ruhr, where the high of iron and steel prizes contributed to the making of his fortune. initially he managed different companies separately in a decentralized fashion, but eventually he united them through a holding company. the largest company of his was the coal mining company "gewerkschaft deutscher kaiser" in hamborn (now part of duisburg) that he had acquired in 1891.