Alexander Joy Cartwright Jr. (April 17, 1820 – July 12, 1892) was a founding member of the New York Knickerbockers Base Ball Club in the 1840s.

In 1837, Gotham member William R. Wheaton drew up rules converting this playground game into a more elaborate and interesting sport to be played by adults.

The major precepts included the stipulations that foul territories were to be introduced for the first time, and the practice of retiring a runner by hitting him with a thrown ball was forbidden.

[10] Cartwright is also erroneously credited for introducing flat bases at uniform distances, three strikes per batter, and nine players in the outfield.

[12] As MLB's Official Historian John Thorn wrote, Cartwright has "a plaque in the Baseball Hall of Fame on which every word of substance is false.

[citation needed] The first clearly documented match between two baseball clubs under these rules took place on June 19, 1846, at Elysian Fields in Hoboken, New Jersey.

[citation needed] In 1849, Cartwright headed to California for the gold rush, and then continued on to work and live in the Kingdom of Hawaii.

One of the leaders of the overthrow movement was Lorrin A. Thurston, who played baseball with classmate Alexander Cartwright III at Punahou School.

[17] New York City librarian Robert W. Henderson documented Cartwright's contributions to baseball in his 1947 book Bat, Ball, and Bishop.

The primary complaint is that touting Cartwright as the "true" inventor of the modern game was an effort to find an alternative single individual to counter the "invention" of baseball by Abner Doubleday.

[20][21] The 2004 discovery of a newspaper interview with fellow Knickerbocker founder William R. Wheaton cast doubt on Cartwright's role.

[23] In 2016, experts verified the authenticity of a set of documents titled "Laws of Base Ball" written in 1857 by New York Knickerbockers president Daniel "Doc" Adams after a discussion with executives of 14 other New York-area clubs.