The Demag company was formed finally 1910 in Duisburg through the union of the Märkische Maschinenbau-Anstalt L. Stuckenholz AG, the Duisburg Mechanical Engineering AG, and the Benrath Machine Works GmbH.

The Märkische Maschinenbau-Anstalt L. Stuckenholz AG traces back to the machine factory Mechanische Werkstätten Harkort & Co., founded 1819 in Wetter an der Ruhr, already beginning the manufacturing of cranes in 1840.

In 1908, they designed what was then the world’s largest floating crane, built for Harland & Wolff in Belfast, which would be used for the building of the passenger liners RMS Olympic and RMS Titanic.[2]

Starting in 1925, Demag also manufactured excavators. They expanded to manufacture locomotives and railroad cars. During the Second World War, armoured fighting vehicles (in particular Bergepanther) were built in the Berlin Staaken plant.

During the buildup to, and during World War II, Demag-designed halftrack military vehicles, such as the armored Sd.Kfz. 250, played an important role during the war, with just over 6,600 built by Demag and their subcontractors.

In 1954, Demag developed their first hydraulic excavators. Demag would soon expand into construction machines, vehicle cranes, moving and conveying engineering (workshop crane and control devices), steel mill technology (complete metallurgical plants, in particular continuous casting equipment), compressors, and compressed air engineering. The company also became a world leader in the manufacturing of injection moulding machines. Demag’s B504 was the world’s first 360-degree, crawler mounted hydraulic excavator when it came out in 1954. Surprisingly advanced for its day, the ½ yard machine featured rotating joints on its front end instead of flexible hoses.