The Board of Discipline of the National Baseball League adopts a set of rules to suppress rowdy ball playing. John T. Brush will later say that the resolution, which he proposed, “has worked like a charm.”

This Day In Baseball

On May 1, 1898 — The Board of Discipline of the National Baseball League adopts a set of rules to suppress rowdy ball playing. John T. Brush will later say that the resolution, which he proposed, “has worked like a charm.”

Source
Baseball Reference May 1