On April 22, 1876, the first national league baseball game was played. The two teams that played were the Boston Red Caps and the Philadelphia Athletics. The Boston Red Caps won the game 6-5.  

       When this game was played these teams were not professional yet, but in 1875 an Illinois businessman and the owner of the baseball team Chicago White Stockings, William Hulbert, was allowed to emerge as the founder of a much more stable National League which included 8 different teams including the Boston Red Caps and the Philadelphia Athletics. Hulbert set new rules to improve the success rate of the teams and their games. Since then, there have been many improvements to the game of baseball which makes it one of the top exciting sports in the United States.  

https://www.history.com/this-day-in-history/first-national-league-baseball-game