The most important early organized baseball club was established in 1845 by some young men in New York City. These young men, under the leadership of Alexander Cartwright and later by Dr. Daniel L. Adams, called their club the Knickerbocker Base Ball Club. The Knickerbockers developed a set of 20 rules which first published in 1845, defined the playing field with a home plate and 3 additional bases set apart at specific distances. They abolished plugging and replaced it with the practice of tagging runners or forcing them out at a base. the first modern baseball game was carried out On June 19, 1846 by the Knickerbockers. The Knickerbocker’s style of played spread rapidly during the 1850s, when baseball clubs formed throughout New York City and adopted the new rules. By the mid-1850s crowds of several thousands were not uncommon at baseball games in the New York City area. During the Civil War the New York Game spread rapidly as Union soldiers introduced the game in places where they traveled. By the end of the war in 1865, the game had become the most popular variety of baseball throughout the country. Soon after, the name New York Game disappeared-it became simply baseball.