Godfathers of Electrodynamics

James Clerk Maxwell
1831-1879

Andre-Marie Ampere
1775-1836

Michael Faraday
1791-1867

James Clerk Maxwell most commonly known for his correction or rather addition to Ampere's Law.
"Maxwell's Equations" are the four governing equations for all electrodynamics. Maxwell proposed and established that light was a dynamic effect of electricity and magnetism. He is known as the scientist that unified electricity and magnetism.

Michael Faraday was known for his experimentation abilities. He never had any high level formal education and was still able to understand and accomplish so much. Faraday discovered induction which is the fundamental idea behind things like the transformer. He also has the SI unit for Capacitance named after him (Faraday) and there's Faraday's Law which is one of the four fundamental equations of electrodynamics.

Andre-Marie Ampere is known to be the discoverer of the relationship between electricity and magnetism. He was able to demonstrate to people that two wires carrying current attract and repel each other depending on the direction of current. Ampere also coined the name electrodynamics, but he was French so he would say, "electro-dynamiques." Ampere's law is one of the four fundamental equations of "electro-dynamiques."

There are many others who have contributed to the study of electrodynamics that don't have their pictures above:

Georg Simon Ohm - Ohm's Law named after him and the SI unit measuring electrical resistance (Ohm)
Joseph Henry - The SI unit for measuring inductance is named after him (Henry)
Nikola Tesla - The SI and most commonly used unit for measuring magnetic field strength (Tesla)
Hendrick Lorentz - Lorentz Law

and many more ....