Which pitcher threw MLB's first official perfect game on June 12, 1880?

The first official MLB perfect game was thrown by Lee Richmond on June 12, 1880.

Richmond pitched for the Worcester Worcesters against the Cleveland Blues at the Worcester County Agricultural Fairgrounds. He retired all 27 batters in order during a 1–0 victory, completing the game in about 1 hour and 26 minutes. The decisive run came in the fifth inning, while an unusual 9–3 putout helped preserve the perfecto when right fielder Lon Knight threw out Bill Phillips at first base.

The achievement looked different from a modern perfect game because baseball’s rules were still evolving. Pitching was underhand, the pitcher’s box was only 45 feet from home plate, eight balls produced a walk, and foul balls could sometimes be caught after one bounce. John Montgomery Ward threw the second major-league perfect game only five days later. Some historians debate whether these early games should be compared directly with modern perfectos, but MLB convention recognizes Richmond as the first.