Introduction
Religion is something that virtually all humans have in common. In all corners of the world and in all eras of history, people have wondered about the meaning of life, how to make the best of it, what happens afterwards, and if there is anyone or anything "out there".
Christianity is the name given to that definite system of religious belief and practice which was taught by Jesus Christ in the country of Palestine, during the reign of the Roman Emperor, Tiberius, and was promulgated, after its Founder's death, for the acceptance of the whole world, by certain chosen men among His followers (New Advent).
The goal of this paper is to provide information on the various answers about Christianity, as well as the rituals and customs that go along with them. It will attempt to summarize the general consensus of Christian beliefs on everything from God to the afterlife.
Origin of Christianity and its relation with other religions
According to the accepted chronology, these began their mission on the day of Pentecost, A.D. 29, which day is regarded, accordingly, as the birthday of the Christian Church. In order the better to appreciate the meaning of this event, we must first consider the religious influences and tendencies previously at work in the minds of men, both Jews and Gentiles, which prepared the way for the spread of Christianity amongst them. The whole history of the Jews as detailed in the Old Testament is seen, when read in the light of other events, to be a clear though gradual preparation for the preaching of Christianity. In that nation alone, the great truths of the existence and unity of God, His providential ruling of His creatures and their responsibility towards Him, were preserved unimpaired amidst general corruption. The ancient world was given to Pantheism and creature-worship; Israel only, not because of its "monotheistic instinct", but because of the periodic interposition of God through His prophets, resisted in the main the general tendency to idolatry. Besides maintaining those pure conceptions of Deity, the prophets from time to time, and with ever increasing distinctness until we come to the direct and personal testimony of the Baptist, foreshadowed a fuller and more universal revelation a time when, and a Man through Whom, God should bless all the nations of the earth (Keating).
Christians Beliefs
Christianity tends to take beliefs quite seriously. The early fathers and councils carefully distinguished between "orthodoxy" from "heresy" in an effort to preserve what they saw as the true Christian message. In the Middle Ages, established doctrine was carefully safeguarded, and in the 16th century, reformers called for the stripping away of superfluous doctrines and emphasized true faith as the only requirement for salvation. Christian beliefs remain important today: the many denominations within Christianity center primarily around matters of doctrine rather than practice. Given the great historical attention that has been devoted to it, the 2,000 years' worth of available writing on its many subjects, and its sometimes complex philosophical arguments, Christian doctrine can be an intimidating subject to tackle, especially for the beginner. The following articles therefore attempt to summarize the general consensus of Christian beliefs on everything from God to the afterlife, with historical development and denominational differences taken into account as much as possible (Religion Facts).
Like Jews and Muslims, Christians believe one God who created the world and takes an interest in the humans who inhabit it. This article explores what Christians believe about the characteristics and nature of God. The major theological belief that Jews and Muslims do not share, the doctrine of the Trinity
God - The Christian God is a personal God. This does not mean that God is a human being, but that God has "personality" and the capability of both relationships with other personal beings. This is seen clearly in both the Old and New Testaments, in which God is described in strongly personal terms (father, shepherd, etc.) and establishes relationships with human beings. In this belief, Christianity is like Judaism and Islam but very different from deism or the theism of Greek philosophy. In the latter systems, God is an impersonal force that causes the world to exist but does not interact with it.
Jesus Christ – For Christians, Jesus is God's only begotten son. He came from the throne of His Father to the womb of a woman. Jesus became Son of Man that we might become sons of God. He was conceived by the Holy Spirit, and born of a virgin. He lived in poverty, and was unknown outside of Nazareth. Jesus had neither wealth nor influence. He paid completely for the sins of all who believe in Him and will set them free from the certain judgment and eternal condemnation of God that was to fall on all humans (Allaboutjesus).
Holy Spirit - The Holy Spirit is a real person who came to reside within Jesus Christ's true followers after Jesus rose from the dead and ascended to heaven (Acts 2). The Holy Spirit is not a vague, ethereal shadow, nor an impersonal force. He is a person equal in every way with God the Father and God the Son. He is considered to be the third member of the Godhead (everystudent).
Conclusion
Christianity is the name given to that definite system of religious belief and practice which was taught by Jesus Christ in the country of Palestine, during the reign of the Roman Emperor, Tiberius, and was promulgated, after its Founder's death, for the acceptance of the whole world, by certain chosen men among His followers. Christianity tends to take beliefs quite seriously. Christians believe one God who created the world and takes an interest in the humans who inhabit it. God is a personal God, but this does not mean that God is a human being. Jesus is God's only begotten son. He came from the throne of His Father to the womb of a woman. The Holy Spirit is a real person who came to reside within Jesus Christ's true followers after Jesus rose from the dead and ascended to heaven.

References

Keating, J. (2009, July 24). In Christianity. Retrieved July 24, 2009, from http://www.newadvent.org/cathen/03712a.htm
Religion Facts, (2009, July 24). In Christians Beliefs. Retrieved July 24, 2009, from http://www.religionfacts.com/christianity/beliefs.htm allaboutJesuschrist.org, (2009, July 24). In Who is Jesus?. Retrieved July 24, 2009, from http://www.allaboutjesuschrist.org/who-is-jesus-christ.htm
Everystudent, (2009, July 24). In Who is the Holy Spirit?. Retrieved July 24, 2009, from http://www.everystudent.com/forum/hspirit.html