In 1859, the Central Commission of Focsani elaborated a Constitution draft that inspired the Constitution of 1866, a project inspired by the Belgian Constitution of 1831. This draft integrated a fi rst coherent vision of fundamental rights and introduced the notion of a representative mandate. We can not talk about guaranteeing the principle of separation of powers in the classical form, but the prevailing constitutional doctrine in Europe at that time was that of the parliamentary government through which the Government had more rights in the relationship with the Parliament. The Central Commission’s draft introduced several mechanisms specifi c to the parliamentary regime and paved the way for its introduction through the 1866 Constitution. The period that begins with the Paris Convention of 1858 and ends with the adoption of the 1866 Constitution coincides largely with the period of the reign of Al. I. Cuza, a period in which the parliamentary regime functioned faultily, but was fi nally recognized as the best form of political organization for the Principalities.