In its early years the Church was small geographically and numerically. For roughly the first 100 years the Church was made up exclusively of Jews in the area of Jerusalem. But as the Church began to grow and spread across the Roman Empire it incorporated Jews, Gentiles, rich, poor, Romans, freemen, and even slaves. By the third century one out of ten people in the Roman Empire was a Catholic. Just as the word Trinity was appropriated to describe the nature of God, so the term catholic was appropriated to describe the nature of Christ’s body, the Church, from the 2nd Century until today.
As mentioned earlier St. Ignatius is the first to use the word catholic in reference to the Church. Another early instance of the word catholic is associated with St. Polycarp, Bishop of Smyrna: “The Church of God which sojourns in Smyrna, to the Church of God which sojourns in Philomelium, and to all the dioceses of the holy and Catholic Church in every place” Also it was written: “When Polycarp had finished his prayer, in which he remembered everyone with whom he had ever been acquainted . . . and the whole Catholic Church throughout the world.” AND “Now with the Apostles and all the just [Polycarp] is glorifying God and the Father Almighty, and he is blessing our Lord Jesus Christ, the Savior of our souls, and the Shepherd of the Catholic Church throughout the world”
Clearly, thru historical writings of the Apostolic and Church Fathers we can see that early in the second century Christians regularly use the word catholic as an established description of the Church. From the second century on thru today we see the term catholic being used consistently by the theologians and writers. One can easily conclude that catholic was a very early description of the Church and was probably used by the apostles themselves.
In the 4th century St. Augustine, relaying the tradition of the early Church, minced no words asserting the importance and wide-spread use of the term catholic when he wrote: “We must hold to the Christian religion and to communication in her Church which is Catholic, and which is called Catholic not only by her own members but even by all her enemies” (The True Religion, 7, 12). And again, “[T]he very name of Catholic, which, not without reason, belongs to this Church alone, in the face of so many heretics, so much so that, although all heretics want to be called Catholic, when a stranger inquires where the Catholic Church meets, none of the heretics would dare to point out his own basilica or house” (Against the Letter of Mani called “The Foundation”, 4, 5).
Some people today try to make a distinction between Catholic with a capital “C” and catholic with a small “c”, but such a distinction is a recent development and unheard of in the early Church.