By 1887, Nikola Tesla secured seven patents for components of his alternating current system. In 1888, George Westinghouse offered to hire Tesla to develop the AC system, and that's when the Current War really got underway.
In 1857 Nikola Tesla began work on direct current motor issues. In 1884, he approached Thomas Edison with ideas about alternating current, but Edison championed direct current. Their disagreement led to one of history's most famous scientific rivalries.