Andre-Marie Ampere was the first scientist to theorize about a link between electricity and magnetism. The French physicist and mathematician was also the first scientist to attempt a mathematical explanation of the phenomenon.
Ampere first became interested in the field of electromagnetics when his friend Francois Arago shared a discovery with him. Danish physicist Hans Christian Orsted had discovered that a magnetic needle would move in response to electric current. Ampere's broad educational background in advanced math, chemistry, philosophy and physics directly contributed to his later discoveries. The marriage of these fields fueled his research, which laid the foundation for the electromagnetics field. His contributions were so significant that electric current is measured using the ampere, which is named after him.