On September 11, 1886, catcher Cornelius McGillicuddy, better known as Connie Mack, made his major league debut with the Washington Nationals (a.k.a. Senators). The Nationals defeated Philadelphia, 4-3, at Capitol Park in Washington.
Connie Mack went on to become the longest-serving manager in Major League Baseball history. He holds records for wins (3,731), losses (3,948), and games managed (7,755).
Connie Mack baseball card, 1887 (Wikimedia Commons)