For instance , Christy Mathewson started pitching in 1901 , had his most glorious years during that decade .
Was in the twilight of Christy Mathewson 's career when ERA became an official stat .
For instance , Christy Mathewson started pitching in 1901 , had his most glorious years during that decade , and was in the twilight of his career when ERA became an official stat .