Nikola Tesla (Serbian Cyrillic: ?????? ?????) (10 July 1856 ? 7 January 1943) was an inventor, physicist, mechanical and electrical engineer. Born in Smiljan, Croatian Krajina, Austrian Empire, he was an ethnic Serb subject of the Austrian Empire and later became an American citizen. An example of Tesla's views regarding his ethnic origin is the quote "I'm equally proud of my Serbian origin and my Croatian homeland."  Tesla is best known for his many revolutionary contributions in the field of electricity and magnetism in the late 19th and early 20th century. Tesla's patents and theoretical work formed the basis of modern alternating current electric power (AC) systems, including the polyphase power distribution systems and the AC motor, with which he helped usher in the Second Industrial Revolution. Contemporary biographers of Tesla have deemed him "The Father Of Physics" and "the man who invented the twentieth century" and "the patron saint of modern electricity."
After his demonstration of wireless communication (radio) in 1894 and after being the victor in the "War of Currents", he was widely respected as America's greatest electrical engineer. Much of his early work pioneered modern electrical engineering and many of his discoveries were of groundbreaking importance. During this period, in the United States, Tesla's fame rivaled that of any other inventor or scientist in history or popular culture, but due to his eccentric personality and unbelievable and sometimes bizarre claims about possible scientific and technological developments, Tesla was ultimately ostracized and regarded as a "mad scientist". Never having put much focus on his finances, Tesla died impoverished at the age of 86.