Below is the listing of the most important events in the Major Leagues as tracked by FanSeeStats. Year links go to Blog.FanSeeStats.com.
To see the annual events go to The Year in Major Leagues.
| 1857 | NABBP established – 1st Proto-League for Sport and Baseball |
| 1871 | NABBP replaced by NA – 1st Elite League for Sport and Baseball |
| 1876 | NA replaced by NL – 1st Major League for Sport and Baseball |
| 1882 | NL vs AA vs LA – 1st Major League Rivalry for Sport and Baseball that lasted for 10 years |
| 1883 | MWCHT – 1st Proto-League for Hockey |
| 1884 | NL vs AA vs UA – 2nd Major League Rivalry for Baseball that lasted for 1 year World Series – 1st cross-league championship for Sport and Baseball |
| 1887 | MWCHT replaced by AHCA – 1st Elite League for Hockey |
| 1890 | NL vs AA vs PL – 3rd Major League Rivalry for Baseball that lasted for 1 year |
| 1893 | Stanley Cup challenge – 1st cross-league championship for Hockey |
| 1894 | WL – a new Elite-League for Baseball that would eventually become a Major-League |
| 1899 | AHCA replaced by CAHL – 2nd Elite-League for Hockey |