Wilhelm Steinitz (May 17, 1836 - August 12, 1900), a Bohemian master (now Czechia) was the first official World Champion (1886 - 94). He took the unofficial title from Adolf Anderssen in 1866. He won the first official World Championship against Johannes Zukertort in 1886 and lost it to Emanuel Lasker in 1894 never regaining it.
Over his 28 years at the top he used two completely different systems. He initially played the popular all-out attacking style. Later he patented the completely new positional style. It was practically bullet-proof against the traditional romantic style.
This new style was denounced as a negative, cowardly style of play. But Steinitz showed it could be used to launch stunning attacking combinations. In the end his ideas won out and were adopted by all leading players. Steinitz was the first positional strategist.