The annual gathering of delegates from the prominent base ball clubs of the United States took place in New York on the night of Dec. 13, 1865, the occasion being the ninth annual meeting of the National Association of Base Ball Players...-Mears Baseball Scrapbook, Volume 4, 1856-1907
...[A] call was made for the report of the Nominating Committee, in order to have the claims of new clubs fully settled, with a view to their voting, and Mr. Thors, chairman of the committee, proceeded to read the names of sixty ! new clubs, applicants for representation in the Convention. During the reading of the names as those of clubs from distant points were announced, considerable applause followed, especially in the case of the clubs from Kansas, Missouri, Kentucky, Tennessee and Maine. After those clubs had been favorably reported upon and all had passed in their credentials and paid their dues, considerable discussion arose in relation to the admission of such clubs whose applications had been informal or not in the order required by the rules...
This article obviously comes from late 1865 or, perhaps, early 1866 and gives a report of the happenings at the 1865 convention of the NABBP. Among the "list of clubs now belonging to the Convention, and the names of their delegates" is the "Empire Club of St. Louis, Mo." who was represented by Henry Clay Sexton. There has always been some confusion in my mind about which St. Louis club was the first to join the NABBP, the Empires or the Unions, and there was evidence supporting each club's claim. This article appears to settle that little argument.
It should also be noted that Sexton was elected Second Vice-President of the Association.