ONSTAGE is the online data collection about Amsterdam’s first and most prominent public theatre venue: the Schouwburg. In theatre history, the Amsterdam Schouwburg has a unique stand for the complete and continuous account books, programming and administration of annual playlists, expenses and revenues which, as a most sensitive finger to the theatre’s pulse, provide access and analytical tools for the theatre’s artistic business from its foundation in 1638 until today. Launched in 2015, ONSTAGE contains the theatre’s programme per date, supplemented with its revenues. As linked data, ONSTAGE is a key instrument for performance details about any individual play in the Schouwburg. For each drama play, it holds information like the premiere date or its performance frequency per season. On a larger scale, ONSTAGE shows the plays’ histories over time and their life cycles on stage from premiere until final performance. Moreover, providing the financial revenues per performance, the ONSTAGE data system has a proxy for the Schouwburg’s occupation per performance and, thus, for the numbers of attendees.