As a historian, and a historian with a particular interest in sport, Mike Cronin understands something about tribes. They are as important as fact and scholarly study in understanding the world around us, he believes. They are as important in the popular understanding of our past as the work historians do. Cronin’s most recent publication, written with Mark Duncan, Revolutionary Times – Ireland 1913-23: The Forging of a Nation is a wonderfully produced book, which tells the story of that decade. It is a decade we are still arguing about today, which is where sport comes in. “I always say…