Paganism (from classical Latin pāgānus "rural, rustic", later "civilian"), is a term first used in the fourth century by early Christians for people in the Roman Empire who practiced polytheism. This was either because they were increasingly rural and provincial relative to the Christian population, or because they were not milites Christi (soldiers of Christ). Alternate terms in Christian texts for the same group were hellene, gentile, and heathen. Ritual sacrifice was an integral part of ancient Graeco-Roman religion and was regarded as an indication of whether a person was pagan or Christian.
Paganism was originally a pejorative and derogatory term for polytheism, implying its inferiority. Paganism has broadly connoted the "religion of the peasantry". During and after the Middle Ages, the term paganism was applied to any unfamiliar religion, and the term presumed a belief in false god(s). Most modern pagan religions existing today - Modern Paganism, or Neopaganism - express a world view that is pantheistic, polytheistic or animistic; but some are monotheistic.
The origin of the application of the term pagan to polytheism is debated. In the 19th century, paganism was adopted as a self-descriptor by members of various artistic groups inspired by the ancient world. In the 20th century, it came to be applied as a self-descriptor by practitioners of Modern Paganism, Neopagan movements and Polytheistic reconstructionists. Modern pagan traditions often incorporate beliefs or practices, such as nature worship, that are different from those in the largest world religions.
Contemporary knowledge of old pagan religions comes from several sources, including anthropological field research records, the evidence of archaeological artifacts, and the historical accounts of ancient writers regarding cultures known to Classical antiquity.
"The Catholic Church has never fostered an attitude of contempt or outright rejection of pagan teachings but, rather, has completed and perfected them with Christian doctrine, after purifying them from all dross of error. So, too, the Church, to a certain extent, consecrated native art and culture..., as well as the special customs and traditional institutions of the people; she has even transformed their feast days, leaving unchanged their methods of computation and their form, but dedicating them to the memory of the martyrs and to the celebration of the sacred Mysteries." We Ourselves have already expressed Our thoughts on this matter as follows: "Wherever artistic and philosophical values exist which are capable of enriching the culture of the human race, the Church fosters and supports these labours of the spirit. The Church, however, which is so full of youthful vigour and is constantly renewed by the breath of the Holy Spirit, is willing, at all times, to recognize, welcome, and even assimilate anything that redounds to the honour of the human mind and heart, whether or not it originates in parts of the world washed by the Mediterranean Sea, which, from the beginning of time, had been destined by God's Providence to be the cradle of the Church." (Papal Encyclical, Princeps Pastorum, 28 November 1959).