Galileo Ferraris

Electric Motor Concept
May 1885:

Galileo Ferraris builds in Turin the first electric motor based on the principle of a rotating magnetic field.

In its simplest implementation it is composed by two orthogonal coils supplied with sinusoidal currents, at a time shift of a quarter of cycle, 90°. Each coil generates a pulsating magnetic field, the sum of the which is a rotating field.

Galileo Ferraris would not patent his invention.
Story goes that Tesla had the idea of three-phase rotating fiels while walking in Budapest in 1882. He found no interested parties in Europe and migrated to America, where in May 1888 he patented the AC motor, based on the principle of a three-phase rotating magnetic field.