In addition to being designed to fit down in a cup, the #2 cast iron hole marker was made with an exceptionally thick/heavy base that allowed it to stand up on the green, so a golfer could putt at the base. I am not sure of the age of these items. The #2 hole marker is the oldest, and possibly approaches the early part of the twentieth century. But I am going to simply say mid-twentieth century for the #1 hole marker.