The Colonial Government of Upper and Lower Canada existed from 1791 to 1841 and was hierarchical in structure. At the head were governors appointed for two years to rule each territory. They oversaw legislative and executive councils. The legislative assembly allowed voting only for wealthy white men. It included conservative and reformer parties, with conservatives supporting the existing hierarchy and reformers wanting more responsible government. Frustration with the colonial system led to rebellions in 1837, prompting reforms by Lord Durham to increase representation and unite the colonies.