Answer by taking a quote from the following article:

Albert Goodwill Spalding (September 2, 1849 - September 9, 1915) was an American pitcher, manager and executive in the early years of professional baseball, and the co-founder of A.G. Spalding sporting goods company. He was born and raised in Byron, Illinois. He played major league baseball between 1871 and 1878. Spalding set a trend when he started wearing a baseball glove, and eventually opened his sporting goods store.

In the months after signing for Chicago, Hulbert and Spalding organized the National League by enlisting the 2 major teams in the East and the 4 other top teams in what was then considered to be the West, also known as the jungle. Joining Chicago initially were the leading teams from Cincinnati, Louisville, and St. Louis. The owners of these western clubs accompanied Hulbert and Spalding to New York where they secretly met with owners from New York City, Philadelphia, Hartford, and Boston. Each signed the league's constitution, and the National League was officially born. "Spalding was thus involved in the transformation of baseball from a game of gentlemen athletes into a business and a professional sport." Although the National Association held on for a few more seasons, it was no longer recognized as the premier organization for professional baseball. Gradually, it faded out of existence and was replaced by myriad minor leagues and associations around the country.  In 1886, with Spalding as President of the franchise, the Chicago White Stockings, (today's Chicago Cubs), began holding spring training in Hot Springs, Arkansas, which subsequently has been called the "birthplace" of spring training baseball. The location and the training concept was the brainchild of Spalding and his player/manager Cap Anson, who saw that the city and the natural springs created positives for their players. They first played in an area called the Hot Springs Baseball Grounds. Many other teams followed the concept and began training in Hot Springs and other locations.  In 1905, after Henry Chadwick wrote an article saying that baseball grew from the British sports of cricket and rounders, Spalding called for a commission to find out the real source of baseball. The commission called for citizens who knew anything about the founding of baseball to send in letters. After three years of searching, on December 30, 1907, Spalding received a letter that (erroneously) declared baseball to be the invention of Abner Doubleday. The commission, though, was biased, as Spalding would not appoint anyone to the commission if they believed the sport was somewhat related to the English sport of rounders. Just before the commission, in a letter to sportswriter Tim Murnane, Spalding noted, "Our good old American game of baseball must have an American Dad." The project, later called the Mills Commission, concluded that "Base Ball had its origins in the United States" and "the first scheme for playing baseball, according to the best evidence available to date, was devised by Abner Doubleday at Cooperstown, N.Y., in 1839."  Receiving the archives of Henry Chadwick in 1908, Spalding combined these records with his own memories (and biases) to write "America's National Game" (published 1911) which, despite its flaws, was probably the first scholarly account of the history of baseball.

What else was mentioned?
The project, later called the Mills Commission, concluded that "Base Ball had its origins in the United States"