1845 -Alexander Cartwright and the Knickerbocker Base Ball Club codify playing rules; also, first box score of baseball game,
      eight men to a side, is printed in New York Morning News.

1846-At Elysian Fields on June 19 in Hoboken, New Jersey the N.Y. Knickerbockers lose to New York Club in first match
      game under Cartwright’s rules.

1849-Knickerbockers develop first uniforms (colors: blue & white).

1853-First box score of Knick-style game is printed in New York Clipper.

1856-Henry Chadwick becomes the first regular baseball reporter.

1858-First admission (50 cents) charged, for game between All-Star teams representing New York
      and Brooklyn played at Long Island’s Fashion Race Course on July 20.

1859-At Pittsfield, Massachusetts, on July 1, Amherst defeats Williams College 73-32 in first college
      game.

1860-The Excelsiors of Brooklyn make the first “road trip”.Their first stop:Albany’s Washington
      Parade Grounds on July 2.

1862-William Cammeyer’s Union Grounds in Brooklyn is the first enclosed ballpark; it opens on May
      15.

1863-First calling of balls and strike.

1865-Ed Cuthbert of the Keystones steals the first base.

1866-Bob Addy of Rockford employs the first slide to steal a base; the Brooklyn Atlantics’ Tom
      Barlow lays down the first bunt.

1867-First use of curve ball, by W.A. “Candy” Cummings.

1869-The Cincinnati Red Stockings are the first fully professional team; they are also the first team
      to wear knickers.

1870-First listing at bats in bow scores, in the New York Clipper.

1871-First professional league is formed-the National Association; first game: Cleveland Forest City’s
      lose 2-0 at Fort Wayne on May 4; first batting averages printed in The Dime Base Ball
      Player.

1873-First doubleheader: Resolutes vs. Boston, July 4.

1874-Boston Red Stockings and Philadelphia Athletics conduct first foreign tour.

1875-Philadelphia’s Joe Borden hurls first no-hitter in pro ranks on
    July 28.

1876-National League’s first game: Boston at Philadelphia on April 22.

1877-International League becomes the first minor league; Tecumseh’s and Maple Leafs are the first
      foreign professional teams; first professional gambling scandal-four Louisville players
      expelled from game.

1878-Turnstiles introduced; Paul Hines of Providence wins first triple Crown and executes first unassisted triple play (May 8); Bud Fowleris first black in pro ball,
     for Lynn Live Oaks of International Association.

1879-Reserve clause first used.

1880-First night game-between two department store teams, at Natasket Beach in Massachusetts’
      Worcester’s Lee Richmond throws first perfect game, against Cleveland on June 12.

1882-American Association introduces first salaried umpiring staff; first postseason playoff; first
      professional doubleheader, Providence vs. Worcester, September 25; Paul Hines is first
      player to wear sunglasses in field.

1884-First “third major league,” the Union Association; first blacks in Major League Baseball-Moses
      and Weldy Walker of Toledo (AA); hit by pitch allows batter to take first base.

1885-Umpires and catchers use first chest protectors.

1886-Players organize first union, “The Brotherhood of BAL Players”; first spring training camp
      (Chicago White Stockings at Hot Springs, Arkansas).

1887-Charles Zimmer is first catcher to play consistently behind the batter; Baltimore’s Mike Griffin
      of Baltimore and Cincinnati’s George “White Wings” Tebeau are the first to homer in their
      first major league at bat; both do it on the same day, April 16.

1888-First round-the-world baseball tour by Chicago White Stockings and all-star squad; “Casey at
      the Bat” makes it first debut in print and on the stage.

1892-National League allows Sunday baseball; first pinch homer, by Brooklyn’s Tom Daly on May
      24.

1894-Boston’s Bobby Lowe is first major league player to smash four homers in one game.

1900-First pinch-hit grand slam, by St. Louis pitcher Mike O’Neill on September 4.

1901-First American League game; Cleveland loses 8-7 at Chicago on April 24.

1903-First modern World Series; Boston defeats Pittsburgh five games to three.

1907-Giants catcher Roger Bresnahan introduces chin guards.

1909-First concrete-and-steel-park opens – Philadelphia’s Shibe Park; Cleveland’s Neal Ball turns
      first modern unassisted major league triple play in majors, on July 19; William Howard Taft
      is first President to throw out “fist ball”.

1910-First cork-centered ball.

1911-First MVP Awards to the Cubs’ Frank Schulte and the Tigers’ Ty Cobb.

1917-First “knothole gang” organized in St. Louis.

1920-First Japanese pro team, the Nihon Undo Kyokai; first team to draw one million fans, Yankees
      with 1,289,422.

1921-First baseball commissioner, Kenesaw Mountain Landis; First radio broadcast of a game, by
      Harold Arlin of KDKA from Forbes Field on August 5; first World Series broadcast (Yankees
      vs. Giants).

1923-Babe Ruth becomes first player to earn $50, 000 in a season.

1926-First amplifiers used (at Polo Grounds).

1930-First successful night ball in minors.

1933-First All-Star Game, at Chicago’s Comiskey Park on July 9.

1935-First major league night game; Phils at Reds, May 24.

1936-First professional league in Japan; first players elected to Hall of Fame (Cobb, Ruth, Mathewson, Wagner, Johnson).
 
 

1939-First American League night game, at Philadelphia Shibe Park on May 16; first televised game, from Ebbets Field on
      August 26.

1941-Dodgers are first club to wear batting helmets.

1946-Montreal’s Jackie Robinson is the century’s first black professional player; first team to draw two million fans, Yankees
      with 2,265,512.

1947-Robinson becomes first modern major league black player; Cleveland’s Larry Doby is first black player in AL; first
      BBWAA Rookie-of-the-Year Awards; Hank Greenberg becomes the first $100,000 player.

1951-Emmett Ashford is first black pro umpire (Southwestern International League); first game televised coast-to-coast (last
      game of NL Playoff); first nationally televised World Series (Yankees vs. Giants); first true baseball encyclopedia, Turkin
      & Thompson’s The Official Encyclopedia of Baseball.

1956-Don Larsen hurls first World Series perfect game, on October 8.

1956-Frank Umont and Ed Rommel are first major league umpires to wear eyeglasses on field.

1957-First Golden Glove Awards.

1959-Joe Cronin becomes first player to become league president when he assumes head of American League.

1962-Jackie Robinson becomes the first black elected to the Hall of Fame.

1965-First enclosed stadium, the Astrodome, opens on April 9.

1966- First major league black umpire, Emmett Ashford of AL.

1969First major league game outside U.S. (St. Louis at Montreal’s Jarry Park on April 14).
 
 

1970- First Strike by major league umpires – occurs during playoffs.

1971- First night World Series game, Baltimore at Pittsburgh on October 13.
 
 

1972- First major league player strike; Bernice Gera is first female professional umpire.
 
 

1973- The Yankees’ Ron Blomberg becomes the first designated hitter, on April 6.
 
 

1974- First major league Hispanic umpire – Armando Rodriguez in AL>
 
 

1975- Indians hire Frank Robinson as first black manager; first players declared free-agents, on December 23, Andy
      Messersmith and Dave McNally.
 
 

1977- Mike Schmidt earns the first $500,000 salary.
 
 

1978- First team to draw three million fans, Los Angeles Dodgers with 3,347, 945.
 
 

1980- Nolan Ryan earns the first $1,000,000 salary.
 
 

1982- Joel Youngblood becomes the first major league player to play for two different teams (Mets & Expos) in two different
      cities (Chicago & Philadelphia) on same day, August 4.
 
 

1985- Mike Schmidt earns the first $2,000,000 salary.
 
 

1989- Bill White becomes the first black league president (NL); the Griffeys become the first father/son duo to perform
      simultaneously.
 
 

1990- Robin Yount earns the first $3,000,000 salary.
 
 

1991- First modern teams to go from last to first (Twins and Braves) meet in World Series; first team to draw four million fans,
      the Toronto Blue Jays with 4,001,527; Rogers Clemens becomes first player to top five million dollar mark, with $5.38
      million salary.
 
 

1992- First non-US world champion, Toronto Blue Jays.
 
 

1994- First year of three divisions in each league.
 
 

1995- First use of “wild cards” in post-season play.
 
 

1996- First major league game scheduled in Mexico, Mets vs. Padres.

1998-The Mark McGwire and Sammy Sosa homerun race.McGwire sets the homerun record with 70 homeruns in a season.