In 1618 a farmer by the name of Henry Wicker at Epsom in England attempted to give his cows water from a well. They refused to drink because bitter taste of the water. However the farmer noticed that the water seemed to heal scratches and rashes. The fame of Epsom salts spread. Eventually it was recognized to be magnesium sulphate, MgSO4.

Joseph Black recognized magnesium as an element in 1755. It was isolated by Sir Humphry Davy (1778-1829) in 1808 almost 200 years after its discovery. He electrolysised  mixture of magnesia (magnesium oxide, MgO) and mercuric oxide (HgO). Davy's first suggestion for a name was magnium but the name magnesium is now used. 

Michael Faraday produced magnesium metal by electrolysis of fused anhydrous magnesium chloride in 1833. The commercial production of magnesium by electrolysis is credited to Robert Bunsen who in 1852 made a small laboratory cell for the electrolysis of fused magnesium chloride, Bunsen’s modificated cell was used in ‘ The Aluminium and Magnesium Fabrik’ in Hemelingen in Germany for the first commercial magnesium production. They designed and built a new plant for dehydration and electrolysis of molten carnalite.

In 1896 was this process further developed bij ‘Griesheim-Elektron Chemische Fabrik’ who transferred the process to its Bitterfield Works and became the only magnesium producing facility in the world until 1916 and then became part of I.G. Farbenindustrie.

Lloyd Montgomery Pidgeon was an Canadian scientist who was head ad the Department of Metallurgy at the university of Toronto. He developed the magnesium process that bears his name and also new electrolytic processes. 

The name magnesium comes from Magnesia, a district of Thessaly/Greece were it was first found and to this present day a lot of magnesium ore is present in the area.