There can indeed be little doubt that for nearly two hundred years after its establishment in Europe, the Christian community exhibited a moral purity which, if it has been equaled, has never for any long period been surpassed. Completely separated from the Roman world that was around them, abstaining alike from political life, from appeals to the tribunals, and from military occupations; looking forward continually to the immediate advent of their Master, and the destruction of the Empire in which they dwelt, and animated by all the fervor of a young religion, the Christiana found within themselves a whole order of ideas and feelings sufficiently powerful to guard them from the contamination of their age.

Chapter 4 (3rd edition p. 11) - A History of European Morals from Augustus to Charlemagne (1869)