Baseball is one of the oldest sports in the world, and its rules have evolved over time to reflect changes in the game and the way it is played. Here are some of the most significant rule changes in baseball history:

• 1857: The pitcher's mound is moved back from 45 to 60 feet, 6 inches. This change made it more difficult for pitchers to throw strikes, which led to an increase in offense.

• 1889: The number of balls in a walk is reduced from nine to four. This change made it easier for batters to reach base, which also led to an increase in offense.

• 1903: The American League adopts the foul strike rule. This rule makes it a strike if a batter hits a foul ball except after two strikes. This change made it more difficult for batters to avoid striking out, which helped to balance the offense and defense.

• 1920: The spitball is banned. The spitball is a type of pitch that is illegal because it is difficult for the batter to see. This rule change made it easier for batters to hit the ball, which led to an increase in offense.

• 1954: The designated hitter is adopted by the American League. The designated hitter is a player who bats for the pitcher, which allows the pitcher to focus on pitching and not worry about hitting. This rule change has led to an increase in offense in the American League.

• 1969: The pitcher's mound is lowered from 15 to 10 inches. This change made it easier for batters to hit the ball, which led to an increase in offense.

• 1973: The designated hitter is adopted by the National League. This rule change has led to an increase in offense in the National League.

• 2020: The runner on second base rule is implemented in extra innings. This rule change shortens the length of extra innings games and makes them more exciting.

• 2023: This is the year of significant changes that speeds the game up.  There’s a new pitcher’s clock, bigger bases, limited number of pick-off attempts by the pitcher leading to more steals and banning infield shifts reducing defense ability to load up one side of the infield.

These are just a few of the many rule changes that have occurred in baseball history. As the game continues to evolve, it is likely that more rule changes will be made in the future.