David Thomas, a Welsh ironmaster, had been brought to America in 1839 to introduce the hot blast manufacture of anthracite iron by the Lehigh Crane Iron Company. Thomas projected his own company, which was organized on February 14, 1854 and chartered on April 4, 1854; it was named in his honor. Thomas left his post as superintendent at Lehigh Crane and was replaced by his son David Jr. He became trustee of real estate, while his son Samuel was appointed superintendent.