After the Belgian Revolution of 1830, the National Congress decided on the Belgian Constitution and the state structure. Belgium would become a unitary state. A bicameral Parliament was chosen over a unicameral one. The Senate was seen as a more conservative and elite body that served as a counterweight to the more progressive Chamber of representatives. Senators were directly elected, but only those who paid ground taxes were eligible. Only men who paid taxes were allowed to vote. There was also the possibility for the heir to the throne to become senator by right.