After unification, teachers in the former GDR were subject to a critical review that focused both on their professional skills and on potentially compromising aspects of their political past – be it the use of doctrinaire curricula or collaboration with the Ministry of State Security. A large number of teachers were dismissed from the education system, especially in the new federal states governed by the CDU. On July 9, 1991, more than 2,000 teachers from Thuringia protested in front of the Ministry of Education in Erfurt. They opposed what they saw as a questionable review process. The sign reads: "25 years of teaching and now "questions about my professional competence"! Why?"