The government had encouraged inhabitants, especially those in urban areas, to learn Greek, and the common language allowed ideas to be more easily expressed and understood.
In the 16th century, in response to the Protestant Reformation, the Church engaged in a process of substantial reform and renewal known as the Counter-Reformation.
In subsequent centuries, Catholicism spread widely across the world despite experiencing a reduction in its hold on European populations due to the growth of Protestantism and also because of religious skepticism during and after the Enlightenment.
The New Testament records Jesus' activities and teaching, his appointment of the twelve Apostles, and his instructions to them to continue his work.
Catholics hold that Saint Peter was Rome's first bishop and the consecrator of Linus as its next bishop, thus starting the unbroken line which includes the current pontiff, Pope Francis.
In 313, the struggles of the Early Church were lessened by the legalisation of Christianity by the Emperor Constantine I.
In 380, under Emperor Theodosius I, Catholicism became the state religion of the Roman Empire by the decree of the Emperor, which would persist until the fall of the Western Empire, and later, with the Eastern Roman Empire, until the Fall of Constantinople.
With Licinius, (Eastern Roman emperor), he issued the Edict of Milan which mandated toleration of all religions in the empire.
The edict had little effect on the attitudes of the people.
On the other hand Commodus and other villainous emperors rather favoured them." Religious philosopher Simone Weil wrote: "By the time of Constantine, the state of apocalyptic expectation must have worn rather thin.
[The imminent coming of Christ, expectation of the Last Day - constituted 'a very great social danger.'] Besides, the spirit of the old law, so widely separated from all mysticism, was not so very different from the Roman spirit itself.
The Second Vatican Council in the 1960s introduced the most significant changes to Catholic practices since the Council of Trent four centuries before.