Contrary to the advice of Jesus Christ who told people not to call anyone "father", Christians called their eminent bishops who were theologians andwriters as Church fathers from the 1st to the 5th centuries. Here the Church is used to mean the whole Christianity. For theological reasons, the period of the Church fathers is of great importance for each of the three large Christian denominations. The area of study which deals with the life and works of the Church Fathers is called patrology. Christian historians have divided Church Fathers in various ways. For example, they have been grouped in terms of the language they speak. Therefore, we have Latin fathers and Greek fathers of the Church. There is also a group of fathers who do not belong to either of these two groups. The present inquiry deals with the subject.

Although the Church of England is in a position between Catholic and Protestant Churches, it is regarded as a branch of Protestant Church inclined towards Catholicism. This church is a quite moderate one in terms of principles and belief, and is regarded among the churches which provide systematic studies on Christian theology, and as a scientific and academic one.The clergymen in the Church of England are ranked according to some regulations and rules. One who is admitted into Christian theological schools has to pass some stages and then begins to help the priests. In this stage he is called deacon. He is introduced to a parish after he passes some special stages and receives the degree of priest from a bishop or archbishop. Among the priests, those who enjoy particular qualifications rise to the rank of bishop. In the Catholic Church of Rome, the Pope is the leader of the Christians of the world and it is incumbent to obey him, because it is thought that he is designated in some way by Christ. The hierarchies of clergymen who serve in the Catholic Church are: the Pope as the leader of the Church, Cardinal, archbishop, bishop, priest and deacon.

Investigating the universal Catholic Church's council proves this claim that throughout the history approach of this church to none Christian religions especially Islam has not been flexible. The view of this church to the other religions in refusal of the universal Councils of the first millennium was the silence literature. As in universal councils of the Middle Ages, their literature turned to invasion and obviously Islam and other religions were anathema to them. But nowadays in their new approach and because of multiple political, social, cultural and scientific factors of the church they have changed position on their anti Islamic approach and the second Vatican's Council has become an assembly for reconsideration of the church's functions. Using a descriptive-analysis method this paper seeks to investigate the change of church's approach in the historical periods of universal councils, specially the second Vatican's Council and shows that how the church in the second Vatican has reformed its doctrinal and social basis about Islam and the other religions.

The church organization has faced many crises in its long life. To overcome such crises, they had no choice but to make reforms in many theological issues in the Second Vatican Council. Discovering the components of the crisis this paper seeks to study the methods of the fathers of the churches in dealing with those crises. The main question is that, how the church could manage the religious-cultural crises caused by theological teachings? And to what extent they were successful? Answering these questions, the church adopted three phases of pre-crisis, during the crisis and post-crisis management. Censorship, banning some books, the Inquisition Court and eventually the torture and execution of the innovators with the charge of heresy were among the early steps. The Church actions during the crisis included the following, Neo-Thomism, New theology, scientific researches and formation of the Second Vatican Council. Post-crisis actions included, reforming the liturgy, the unity of Churches, confronting Communism, religious freedom and admitting Catholic Church's past mistakes.

Religion and religious institutions play a significant role in regulating the relationship between people and government institutions. Uch-Kilisa (Three Churches) has played a special role throughout Armenian history. Etchmiadzin Cathedral is one of those triple churches and the first cathedral in the history of Christianity that was able to unite the divided Armenian people for a stable coexistence with the people of Iran. This research aims to analyze the role of the high church in regulating the relationship of the Armenian people living in the closed countries of Iran during the Qajar period. Findings of the research indicate that Uch-Kilisa as a religious institution during the Qajar period, played a strategic role in regulating the relationship between Armenians and the Iranian government, so that the stability and durability of the Armenian nation were owed to Uch-Kilisa, and the Qajar kings communicated with the Armenians living in Iran through this religious institution.

Egyptian Christians inhabited for a long time in there and they had different roles in the society throughout history. The Orthodox church of Egypt that nowadays is known as the Coptic Orthodox church abdicated from other western and eastern churches after the international Calsdon council, and continued independently. Using a descriptive-analytic method and considering the history of this church, this paper seeks to mention the most important faith and practical features. The author believes that the Coptic Church follows the specific conflicts of Christology at the time of Christian Fathers that was specifically at work between the Antioch and Alexandrian Churches. Consequently, one simplistic nature of Christology is the most important feature of this Church that is influenced by Greek theologies of Alexandrian school of thought. On the other hand, the tie between this Church and monasticism caused its continuation and persistence during the history. Also, this Church has tried to lessen its faith conflicts with the Rom Catholic Church.

Impermissibility of divorce in Christianity and canons deriving from it, like privation of participation in Holy Communion, always causes many difficulties for Christians, particularly for Catholics. In contemporary world the problems, such as civil marriage without following Christian laws and cohabitation in which two persons live together without any canonical and formal marriage, has confronted the church with a great challenge. Finding out that it is necessary to present new ideas about family issues, some theologians like Hans Kung has demanded to reform and alter marriage and divorce laws. In contrast, traditional theologians persist in keeping Christian traditions and speak purely of more pastoral cares, without any alterations in laws. Meanwhile, some theologians like cardinal Kasper, though considering the prohibition of divorce as a dogmatic and inconvertible law, sympathetically accept reconsidering the established divorce dictums in the church. General demands and new ideas of Christian thinkers made the church to form an episcopal council and make decision on the subject. This council didnt make any changes in the biblical laws related to divorce, but showed some flexibility toward its consequences and permitted participation in the Eucharist in the case of the local church identification. This flexibility shows that, though the alteration of Christian dogmas and laws is difficult, it is possible to alter some Christian laws

The Vatican Council Statement II seems to be the Catholic Church's most important encounter with post-Renaissance Enlightenment issues. Before that, a true believer was someone who devoted himself exclusively to serving Christ in the church, and a Christian outside the church was considered a second-class citizen. But after this statement, the communities outside the church were accepted by the church, and according to this decree, the Christians of these communities could also dedicate themselves to the service of Christ. Now, reading the article raises the issue in the minds of the audience that the Catholic Church has been in a weak position in the face of the achievements of the modernity, or since the beginning of the history of Christianity has misunderstood the principles of genuine Christianity, or ignored it have been. According to the translator, any accurate answer to this fundamental question can be a guide to the correct and worthy confrontation of the Islamic world with the emerging problems of the new world.