An aged and extremely rare surviving paper invitation to the First Grand Assembly of the Brotherhood Base Ball Club, hosted on Monday, Oct. 6, 1890 at the Odd Fellows Hall in the Glenmere section of Lynn, MA. A celebratory event, the invitation reflects a full schedule in store for the night’s attendees, complete with several baseball-themed dances. While we cannot definitively confirm it, there is a high probability this invitation is directly associated with the champions of the 1890 Player's League – manager King Kelly's Boston Reds. At that time, in the first organized attempt to unionize, The Brotherhood of Professional Base Ball Players had assembled their Player's League and Boston's team became known locally as "the Brotherhood club." It's worth noting that festivities planned for the evening of Oct. 6 would have occurred exactly two days after Boston's final game of the season on Saturday, Oct. 4 in Pittsburgh. The four-sided invitation, which measures 3.5" wide x 4.75” high, boasts a color illustration on the front featuring a lone fisherman, followed by a full lineup of dances on the inside pages, and a back cover that acknowledges the event’s organizers.