Freiherr Christian Johann Dietrich Theodor von Grotthuss (20 January 1785 – 26 March 1822) was a Baltic German scientist known for establishing the first theory of electrolysis in 1806 and formulating the first law of photochemistry in 1817.

[2] Grotthuss was born in 1785 in Leipzig, Electorate of Saxony, Holy Roman Empire, during an extended stay of his parents away from their home in northern Grand Duchy of Lithuania.

Because of some tensions in the relations between Russia and France, Grotthuss had to leave for Italy where he stayed at Naples for one year.

The electrolysis of water, acids and salt solutions was reported, but a good explanation was missing.

[3] The following two years Grotthuss spent in Rome, some other Italian cities, and Paris, and then went back to Russia via Munich and Vienna.