<P> After the fall of the Roman Empire in the 5th century, there emerged no single powerful secular government in the West . There was however a central ecclesiastical power in Rome, the Catholic Church . In this power vacuum, the Church rose to become the dominant power in the West . The Church started expanded in the beginning 10th century, and as secular kingdoms gained power at the same time, there naturally arose the conditions for a power struggle between Church and Kingdom over ultimate authority . </P> <P> In essence, the earliest vision of Christendom was a vision of a Christian theocracy, a government founded upon and upholding Christian values, whose institutions are spread through and over with Christian doctrine . In this period, members of the Christian clergy wield political authority . The specific relationship between the political leaders and the clergy varied but, in theory, the national and political divisions were at times subsumed under the leadership of the Catholic Church as an institution . This model of church - state relations was accepted by various Church leaders and political leaders in European history . </P> <P> The classical heritage flourished throughout the Middle Ages in both the Byzantine Greek East and the Latin West . In the Greek philosopher Plato's ideal state there are three major classes, which was representative of the idea of the "tripartite soul", which is expressive of three functions or capacities of the human soul: "reason", "the spirited element", and "appetites" (or "passions"). Will Durant made a convincing case that certain prominent features of Plato's ideal community were discernible in the organization, dogma and effectiveness of "the" Medieval Church in Europe: </P> <P>... For a thousand years Europe was ruled by an order of guardians considerably like that which was visioned by our philosopher . During the Middle Ages it was customary to classify the population of Christendom into laboratores (workers), bellatores (soldiers), and oratores (clergy). The last group, though small in number, monopolized the instruments and opportunities of culture, and ruled with almost unlimited sway half of the most powerful continent on the globe . The clergy, like Plato's guardians, were placed in authority...by their talent as shown in ecclesiastical studies and administration, by their disposition to a life of meditation and simplicity, and...by the influence of their relatives with the powers of state and church . In the latter half of the period in which they ruled (800 AD onwards), the clergy were as free from family cares as even Plato could desire (for such guardians)... (Clerical) Celibacy was part of the psychological structure of the power of the clergy; for on the one hand they were unimpeded by the narrowing egoism of the family, and on the other their apparent superiority to the call of the flesh added to the awe in which lay sinners held them...In the latter half of the period in which they ruled, the clergy were as free from family cares as even Plato could desire . </P>

Separation of church and state during the renaissance