While Catholicism varies to some degree in it's teachings and practices from basic Christianity. It's main core doctrines are alike. I have noted contentions throughout the internet as to the purposes and direction of the papacy
and the beliefs that the Catholic Church holds. My ideal situation is to build a bridge between
Christians and Catholics in Christ regardless of what the Church espouses!
Nevertheless some will disagree and find any reason to argue the point! I myself enjoy
the opportunity to share my faith with any who would choose to listen to my beliefs and guess what many of those are Catholics!

Early Catholicism:

The term "Catholic Church"
A letter , in about 107, Saint Ignatius, Bishop of Antioch wrote to Christians in Smyrna, is the earliest surviving witness to the use of the term "catholic Church" (Smyrnaeans, 8). By it Saint Ignatius designated the Christian Church in its universal aspect, excluding heretics, such as those who disavow "the Eucharist to be the flesh of our Saviour Jesus Christ, which suffered for our sins, and which the Father, of His goodness, raised up again" (Smyrnaeans, 7). He called such people "beasts in the shape of men, whom you must not only not receive, but, if it be possible, not even meet with" (Smyrnaeans, 4).

Yet more explicit was the manner in which Saint Cyril of Jerusalem (circa 315-386) used the term "catholic Church" precisely to distinguish this Church from heretical "Churches". He urged: "If ever thou art sojourning in cities, inquire not simply where the Lord's House is (for the other sects of the profane also attempt to call their own dens houses of the Lord), nor merely where the Church is, but where is the Catholic Church. For this is the peculiar name of this Holy Church, the mother of us all, which is the spouse of our Lord Jesus Christ, the Only-begotten Son of God" (Catechetical Lectures, XVIII, 26).

Only slightly later, when Christians still applied the word "priest" only to bishops and not yet to those who are now called "priests" in English, Saint Augustine of Hippo (354-430) wrote:

"In the Catholic Church, there are many other things which most justly keep me in her bosom. The consent of peoples and nations keeps me in the Church; so does her authority, inaugurated by miracles, nourished by hope, enlarged by love, established by age. The succession of priests keeps me, beginning from the very seat of the Apostle Peter, to whom the Lord, after His resurrection, gave it in charge to feed His sheep (Jn 21:15-19), down to the present episcopate.
"And so, lastly, does the very name of Catholic, which, not without reason, amid so many heresies, the Church has thus retained; so that, though all heretics wish to be called Catholics, yet when a stranger asks where the Catholic Church meets, no heretic will venture to point to his own chapel or house.
"Such then in number and importance are the precious ties belonging to the Christian name which keep a believer in the Catholic Church, as it is right they should ... With you, where there is none of these things to attract or keep me... No one shall move me from the faith which binds my mind with ties so many and so strong to the Christian religion... For my part, I should not believe the gospel except as moved by the authority of the Catholic Church."
— St. Augustine (354–430): Against the Epistle of Manichaeus called Fundamental, chapter 4: Proofs of the Catholic Faith[5]
A contemporary of Augustine, St. Vincent of Lerins, wrote in 434 under the pseudonym Peregrinus a work known as the Commonitoria ("Memoranda"). While insisting that, like the human body, Church doctrine develops while truly keeping its identity (sections 54-59, chapter XXIII), he stated: "[I]n the Catholic Church itself, all possible care must be taken, that we hold that faith which has been believed everywhere, always, by all. For that is truly and in the strictest sense 'Catholic,' which, as the name itself and the reason of the thing declare, comprehends all universally. This rule we shall observe if we follow universality, antiquity, consent. We shall follow universality if we confess that one faith to be true, which the whole Church throughout the world confesses; antiquity, if we in no wise depart from those interpretations which it is manifest were notoriously held by our holy ancestors and fathers; consent, in like manner, if in antiquity itself we adhere to the consentient definitions and determinations of all, or at the least of almost all priests and doctors" (section 6, end of chapter II).

Early Roman Architecture
Divergent interpretations of the term "Catholic Church"
Many Christians (and denominations) are commonly considered "catholic". They fall into two groups:

1) those like the Roman Catholic, Eastern Orthodox, Oriental Orthodox, and Anglican Churches having Apostolic Succession from the early Church; and
2) those who claim to be spiritual descendants of the Apostles but have no discern-able institutional descent from the historic Church, and normally do not refer to themselves as catholic.
Of those in the first category, some see their Church as the Catholic Church, others see their Church as only part of the Catholic Church.

For Protestants, most of whom consider themselves to be spiritual descendants (category 2, above), this affirmation refers to their belief in the ultimate unity of all Churches under one God and one Saviour, rather than in one visibly unified institutional Church (category 1, above). In this usage catholic is sometimes written with a lower-case "c". The Western Apostles' Creed, stating "I believe in...the holy catholic church..." (sometimes capitalised), is thus recited in Protestant worship services (with some exceptions such as German Lutherans, who substitute "Christian" for "catholic"). The Nicene Creed likewise declares belief in "one, holy, catholic and apostolic Church". It should be noted historically, however, that apostolicity in the form of tactile succession as well as spiritual descent has been maintained by certain national Lutheran Churches (now part of the Porvoo Communion), and has been restored in this fully visible form to the Evangelical Lutheran Church in Canada and the Evangelical Lutheran Church in America through the procedures of full communion agreements with their national Anglican counterparts.

Brief organizational history of the Church!
The early Catholic Church came to be organized under the three patriarchs of Rome, Alexandria and Antioch, to which later were added the patriarchs of Constantinople and Jerusalem. The Bishop of Rome was at that time recognized as first among them, as is stated, for instance, in canon 3 of the First Council of Constantinople (381) - many interpret "first" as meaning here first among equals - and doctrinal or procedural disputes were oftentimes referred to Rome, as when, on appeal by St Athanasius against the decision of the Council of Tyre (335), Pope Julius I, who spoke of such appeals as customary, annulled the action of that council and restored Athanasius and Marcellus of Ancyra to their sees. The Bishop of Rome was also considered to have the right to convene ecumenical councils. When the Imperial capital moved to Constantinople, Rome's influence was sometimes challenged. Nonetheless, Rome claimed special authority because of its connection to Saint Peter2 and Saint Paul, who, all agreed, were martyred and buried in Rome, and because the bishop of Rome saw himself the direct successor of Saint Peter.

The 431 Council of Ephesus, the Third Ecumenical Council, was chiefly concerned with Nestorianism, which emphasized the distinction between the humanity and divinity of Jesus and taught that, in giving birth to Jesus Christ, the Virgin Mary could not be spoken of as giving birth to God. This Council rejected Nestorianism and affirmed that, as humanity and divinity are inseparable in the one person of Jesus Christ, his mother, the Virgin Mary, is thus Theotokos, God-bearer, Mother of God. The first great rupture in the Church followed this Council. Those who refused to accept the Council's ruling were largely Persian and are represented today by the Assyrian Church of the East and related Churches, which, however, do not now hold a "Nestorian" theology. They are often called Ancient Oriental Churches.

The next major break was after the Council of Chalcedon (451). This Council repudiated Eutychian Monophysitism which stated that the divine nature completely subsumed the human nature in Christ. This Council declared that Christ, though one person, exhibited two natures "without confusion, without change, without division, without separation" and thus is both fully God and fully human. The Alexandrian Church rejected the terms adopted by this Council, and the Christian Churches that follow the tradition of non-acceptance of the Council - they are not Monophysite in doctrine - are referred to as Pre-Chalcedonian or Oriental Orthodox Churches.

The next great rift within Christianity was in the 11th century. Longstanding doctrinal disputes, as well as conflicts between methods of Church government, and the evolution of separate rites and practices, precipitated a split in 1054 that divided the Church, this time between a "West" and an "East". England, France, the Holy Roman Empire, Scandinavia, and Western Europe in general were in the Western camp, and Greece, Romania, Russia and many of other Slavic lands, Anatolia, and the Christians in Syria and Egypt who accepted the Council of Chalcedon made up the Eastern camp. This division is called the East-West Schism.

The fourth major division in the Church occurred in the 16th century with the Protestant Reformation, after which many parts of the Western Church either entirely rejected the teachings of the Roman Catholic Church and became known as "Reformed" or "Protestant", or else repudiated Roman papal authority and accepted decisions by the civil ruler in religious matters.

A much less extensive rupture occurred when, after the Roman Catholic Church's First Vatican Council, in which it officially proclaimed the dogma of papal infallibility, clusters of Catholics in the Netherlands and in German-speaking countries formed the Old-Catholic (Altkatholische) Church and other Independent Catholic Churches.

All of the preceding groups, excluding some Protestants, consider themselves fully and completely Catholic, either as part of the Catholic Church or as the one and only Catholic Church.

The Roman Catholic Church
Main article: Roman Catholic Church
"The Catholic Church", when used not of an abstract invisible entity, but of a visible concrete body of Christians, usually refers to what is also called "the Roman Catholic Church".

This Church does not often use the name "Roman Catholic Church" for itself, except in its relations with other Christian groups. Even in those relations, "Catholic Church" may also appear, as in some documents drawn up in common with the Lutheran World Federation and the Assyrian Church of the East. On the other hand, the Church has in fact applied the adjective "Roman" to itself in its entirety even in some internal documents, such as the Dogmatic Constitution de fide catholica of the First Vatican Council, which was attended by Eastern as well as Western bishops. When it does apply the adjective "Roman" to itself, it understands this word only as pointing to the centrality for it of the see of Rome, with which all its members, laity and clergy alike, are necessarily in full communion. Outsiders, in contrast, considering the use of the name "Catholic Church" by this Church to be contentious, use the term "Roman Catholic Church" to imply that it is only the "Roman" section of some larger, perhaps abstract, entity that they call the Catholic Church and that, in their view, also includes other sections not in communion with Rome, a usage that members of the Church in question in turn see as contentious.

Frequently enough, some members of this Church, especially those of the many other Eastern Rites, apply the term "Roman Catholic Church" not, as in the Church's official documents, to the Church as a whole, but only to its Latin Rite component. Unlike the outsiders just mentioned, these consider communion with the see of Rome essential for all members of the Catholic Church.

" More on Catholicism"

http://catholicism.about.com/cs/saints/