On April 22, 1876, the Boston Red Caps beat the Philadelphia Athletics, 6-5, in the first official National League baseball game. The game, which lasts a little more than two hours, is played in "favorable" weather before 3,000 fans at the Athletics' grounds at 25th and Jefferson streets. "Great interest was manifested in the result," the Philadelphia Inquirer reports, "as it really was the first game of importance played this season."
"The Athletics should have won the game," the newspaper added, "but their fielding was poor." Betting on the game was "about even," according to the Inquirer.
While this was the first official National League game, the teams were not the first in professional baseball—the first pro team was the 1869 Cincinnati Red Stockings. Nor was the NL the first major professional baseball league—the first league was the National Association of Professional BaseBall Players, formed in 1871.
However, the National Association was loosely configured and had no central leadership or authority to govern its teams. Therefore, corruption, gambling, drunkenness and other malpractices became commonplace by 1875 and the league folded. That allowed William Hulbert, an Illinois businessman and owner of the Chicago White Stockings, to emerge as the founder of the much more stable National League.
Hulbert took the six strongest clubs from the National Association—the Boston Red Stockings (which became the Red Caps), Philadelphia Athletics, Hartford Dark Blues, St. Louis Brown Stockings, Chicago White Stockings and New York Mutuals—and the Louisville Grays and Cincinnati Reds to form the National League.
Hulbert put new rules in place that gave the new league a better chance for success than its predecessor. It was an invite-only league and teams had to pay substantial league dues and were subject to league discipline for misbehavior.
In 1876, the pitching mound was 45 feet from home plate instead of today's 60 feet, six inches. Pitches were supposed to be delivered underhanded, but pitchers "violated that rule with impunity," says John Thorn, Major League Baseball's official historian. Nine errant balls walked a batter instead of four in the modern game. Before an at-bat, a batter could specify a high strike zone (waist to shoulders) or low one (waist to shin).