Although he seems not to have given it much thought at time, pioneer baseball writer Henry Chadwick eventually came to regard first-ever convention of clubs-in 1857 in York-as a pivotal moment in game's history. With this convention, Chadwick wrote in 1881, base may be said to date its origin as a regular established sport, with authorized rules to govern it. Before 1857, he recalled, base was played under club rules merely, those of Knickerbocker Club of York prevailing in that city. Different rules governed clubs in England and Philadelphia, but after 1857 convention the 'New York game' began to obtain an extended popularity, and eventually it swallowed up Town Ball, and England game, and ten years afterward York rules became national.1Few baseball historians have accorded this first convention prominence Chadwick gave it; but its effect may be even greater than Chadwick supposed. To grasp its import, we need to see where baseball of 1857 came from-to look back to birth of New York in organization of Knickerbocker Base Ball Club.The baseball we know today traces its rules in a direct and undisputed line back through 1857 convention to founding of Knickerbocker Club on September 23, 1845. Baseball before that date is wreathed in uncertainty, but what we do know is enough to show transformative character of Knickerbockers' first rules.The name base ball and published descriptions of baseball-like bat-and-ball games date back at least to 1796, when a German compilation of games for youth included a detailed account of das englische Base-ball.2 From 1820s on, English and American books of outdoor games for described a game variously called rounders, base ball, and goal ball.3 But early descriptions were just that-descriptions; instructions on how to game. One of distinctive features of Knickerbocker rules of 1845 is that they constitute earliest extant codification of rules for playing baseball.The Knickerbockers' game and its rules transformed baseball from informal for to formal sport for adults. To call pre-Knickerbocker baseball play for children is not to say game was never played by adults. It was. A number of Yorkers played baseball for years before Knickerbockers organized, and there is ample evidence of early bat-and-ball by adults.4 What is distinctive about Knickerbockers' first rules is that they stabilized and (as it turned out) permanently institutionalized baseball as an adult game.5The very fact of club's formal organization gave it a substance and visibility that informal could never achieve. Although baseball historians like Robert Henderson and David Block have shown that development of baseball has been an evolutionary process,6 it is also useful to employ a different analogy: to look at formal organization of Knickerbocker Club as birth of baseball after long gestation. With club established and its rules set down in black and white, everyone could see game more clearly-could ponder rules and observe regularly scheduled club exercise, with its combination of familiarity and uniqueness that made it attractive for adults. With birth of Knickerbockers baseball gained a public face.Important among Knickerbockers' innovations, 1845 rules narrowed focus of by creating foul territory7 and forbade soaking (the practice of retiring a runner by hitting him with a thrown ball).8 These new rules promoted a less helter-skelter, more mannerly (read: more adult) form of exercise. Another rule lengthened distance between bases at least 20-35 percent, further distinguishing playing field from those of children's games.9The founding Knickerbockers did not intend their game as mere entertainment- for adults-but neither did they want it to be seriously competitive. …