Baseball from 1869 to 1969 transformed from a loosely organized pastime into America’s national sport, evolving through foundational rule changes, labor struggles, the rise of major franchises, and the integration of some of the game’s most enduring legends.

The first professional team, the Cincinnati Red Stockings, took the field in 1869, marking the birth of organized pro baseball. The National League was founded in 1876, providing structure and legitimacy, followed by the creation of the American League in 1901. These two leagues formed the modern Major League Baseball structure and began the annual World Series in 1903.

The early era was defined by pioneers like Cap Anson, King Kelly, and Old Hoss Radbourn, who played under evolving rules, often with brutal travel and rudimentary equipment. By the 1910s, Ty Cobb, Walter Johnson, a ...