Task: Text Categorization
Input (English): Some of the last areas to join this group were admitted via the Convention of Gastein, and the Heppenheim program and the Vormarz movements attempted to democratize this organization. Governed by a (*) Bundesrat, it implemented the ideas of Friedrich List. Members adopted the metric system and the Vereinsthaler currency. For 10 points, name this economic union, a precursor to German unification.
Output (English): History