The Orthodox Church, which had possessed enormous property and power in medieval Russia, underwent profound change in Imperial Russia. Although the medieval Russian Church had constructed an administration to exercise its broad spiritual and temporal authority, it exhibited the same organisational backwardness as did the secular regime. The 'clerical estate' that served the Church consisted of three categories: the ruling episcopate, celibate monastic clergy and married secular clergy. Given the dispersion of population, the heterogeneity of local cultures, and the institutional backwardness of the medieval Church, Russian Orthodoxy was actually Russian Heterodoxy, with kaleidoscopic variations in local customs, superstitions and religious practice. In the sixteenth and seventeenth centuries the Church undertook to standardise and purify popular religious practice, but as yet lacked the instrumentalities to make a fundamental 'reformation' in popular religious practice. Parallel with the 're-christianisation' of the folk, the Church began to develop and articulate its social and political teachings.