Christians soon adopted the term to refer to those who taught the message of God's salvation. The first evidence in Christian writing appears around the year 200 by Tertullian, a layman from North Africa. He used it to refer to priests as well as to all who gave instruction in the faith, those who, like the Apostles "follow the Paraclete" (Holy Spirit) as their doctor."

After the official recognition of Christianity in the fourth century and its spread through the Roman Empire, debates began to grow over the correct interpretation of the faith. This led to a number of meetings, councils of the universal Church, where a number of bishops, Eastern and Western, came to the fore as teachers of the faith, eventually labelled "doctors of the Church."

Writing against heretics, Augustine appealed to the teachings of "the most renowned doctors of the Church," listing seven names of early Christian thinkers. In about 435, Vincent of Lerins indentifying the essence of orthodoxy as "what had been believed everywhere, always and by all" stressed the role of Scripture and tradition and referred to ecclesiastical writers as "doctors and masters of the churches."

By the beginning of the Middle Ages, "doctor of the Church" was a familiar term to describe authoritative teachers.

With the renewal of theology in the West in the 12th and 13th century, the role of doctors grew. Although the numbers remained fluid, importance was given to the four official Latin doctors, Ambrose, Augustine, Jerome and Gregory, as well as four Eastern doctors: Athanasius, Chrysostom, Basil, Gregory of Nazianze.

In St. Peter's in Rome, a wooden chair is venerated as the symbol of the teaching authority of the Petrine see. On large marble pillars at the base are four towering bronze figures, two with mitres representing the Western Church (Augustine and Ambrose) and two without mitres representing the Eastern Church (Athanasius and John Chrysostom). They touch but do not actually support the chair which appears to hover in the air as if by divine power.

With the Protestant reformers' emphasis on Scripture alone, greater attention was given by Catholicism to the doctors of the Church. In the 18th century, three popes named doctors in less than a decade. In the 19th century, three Eastern Fathers were among nine named while the 20th century popes named 10, including three women.

An interesting development was initiated by Pope Paul VI who named Teresa of Avila as doctor on Sept. 27, 1970 and then Catherine of Siena a week later.

Paul praised Teresa's teaching as based on "the extraordinary action of the Holy Spirit." He indicated that the title of doctor is not connected to the hierarchical function of the magisterium, adding that "many women have arrived at great heights even to the point of where their words and their writings have become lights and guides for their brethren."

He emphasized the understanding of doctor of the Church as a recipient of special graces for the good of the Church.

Pope John Paul II, the greatest saint-maker in history (more than 280), has named only one doctor, St. Th‚rŠse of Lisieux. She had been declared patroness of the missions in 1929 and John Paul emphasized this role as an example of the missionary mandate of all the baptized.

It appears that politics may have been influential in naming the doctors with the same number for each of the major religious orders: Dominicans, Jesuits, Franciscans and, now with the addition of two Carmelite women, the Carmelites. There are many influential Christian saints, teachers of the Church who could be named as doctors, but only 33 have been officially named and only two were bishops of Rome.

What, then, is a doctor of the Church? In the strict term, the term was first used for the ordained, hierarchical teachers of the fourth and fifth century whose defence of the faith was seen as the criteria for orthodox or correct belief. In the broadest sense, all baptized Christians, inspired by the Holy Spirit, are called to be doctors of the Church as they believe and teach the faith by word and example.

As Paul VI reminded us, not even the popes create doctors, they recognize what the Holy Spirit alone has given to many men and women in the history of the Church.