The Sergeants' Revolt undermined the institutions and coercive structures of the oligarchic state. The young and relatively inexperienced revolutionaries found themselves pushed into the halls of state power by worker and peasant mobilisations. Between September 1933 and January 1934 a loose coalition of radical activists, students, middle-class intellectuals, and disgruntled lower-rank soldiers formed a Provisional Revolutionary Government. This coalition was directed by a popular university professor, Dr Ramón Grau San Martín. The Grau government promised a 'new Cuba' which would belong to all classes, and the abrogation of the Platt Amendment. While the revolutionary leaders certainly wanted diplomatic recognition by Washington, they believed their legitimacy stemmed from the popular support which brought them to power, and not from the approval of the United States' Department of State.