Project proposal under the European Commission 7th Framework Programme for Research, Technological Development and Demonstration. The IRTSNT project proposes a longitudinal and comparative network analysis of sector change, innovation and success in Europe's international third sector and beyond. The central research question: How do long-term developmental trends in Europe’s international third sector compare to non-European international third sector organizations (1948-2012), to what extent do these trends reflect processes of convergence and hybridization, what organizations are most successful, and how can these trends and successes be explained?