The modern Major League Baseball World Series started in 1903 with a championship between the Boston Americans (now Red Sox) and the Pittsburgh Pirates.

Quick Scoop

  • The first official World Series was played in October 1903.
  • It matched the champions of the new American League (Boston) and the established National League (Pittsburgh).
  • Boston won that inaugural series in a best‑of‑nine format, five games to three.

A Bit of Background

  • Earlier “world championship” baseball series were played in the 1880s, but MLB recognizes 1903 as the first true World Series.
  • The event followed a peace agreement between the rival American and National Leagues, turning their rivalry into a formal postseason showdown.

In short: if you’re asking “when did the World Series start,” the answer in baseball history terms is 1903.

TL;DR: The World Series began in 1903 as a postseason showdown between the AL and NL champions, with Boston defeating Pittsburgh in the first edition.

Information gathered from public forums or data available on the internet and portrayed here.