For many centuries, there was no formal world chess championship, but there were nonetheless a select few who achieved fame for their ideas and successes over the chess board, and sometimes even for their writings. Each player below was recognized in his respective time as the strongest chess player in the world. The years indicate the approximate time period when each could be considered world champion in an unofficial capacity.

In the 1850s, America's foremost chess player was a young man from Louisiana named Paul Morphy. In 1858, Morphy traveled overseas to play against the finest competition that Europe had to offer. Morphy annihilated the opposition, including the German attacking genius Adolf Anderssen, who was widely regarded as the strongest player of the day. Morphy had proven himself in every way a World Chess Champion. After his European tour, Morphy returned to the states, and announced his retirement from chess.

Morphy's retirement in 1862 left a vacuum in the chess world, and the simple question, "Who is the best?" lacked a definitive answer. Anderssen was a likely choice, but it wasn't long before people turned their attention to an Austrian chess sensation named Wilhelm Steinitz, whose daring attacking style had earned him the nickname "The Austrian Morphy". When Steinitz defeated Anderssen in 1866, Steinitz was widely regarded as the world's best, and would be for decades to come.