The history of the Theatre Historiography Working Group in IFTR/FIRT provides a case study of how and why the Federation has been transformed by its working groups during the last two decades. Founded in 1992, the historiography group has developed into one of the largest and most active in IFTR/FIRT. Over the last nineteen years, the members of the group, drawn from many of the countries in the Federation, have used the annual meetings to develop a diverse and often challenging scholarship on the history of theatre (broadly defined). By focusing on the basic issues in historiography, the participating scholars have refined their research and writing methods. Moreover, the essays and books, published in several languages, have contributed to major transformations in the methods and topics in performance history. The working group, besides serving as a transnational community for historical scholarship, has also contributed to revisionist methods in the teaching of theatre history in dozens of countries, especially during the last decade.