In October 1901, a very successful Italian scientist and engineer Giovanni Giorgi showed at the congress of the Associazione Elettrotecnica Italiana (A.E.I.) in Rome that a coherent system of units could be achieved by adding an electric unit to the three mechanical units (centimetre, gram, second) of the existing CGS system. The event can be considered as the birth of what is now known as the International System of Units, or SI.