Catacombs

Fresco decorations were typically Roman. However, these early religious wall paintings appear crudely drawn in comparison with other Roman art of the time.
More and more, the purpose of art became to portray the spiritual world. There was no longer any interest in depicting three-dimensional figures. Rather, the new Christian philosophy scorned attention to the material body and encouraged its followers to focus on the soul. Painting mirrored this ideology. Without any real precedents for painting in the Jewish and Christian religions, these early artists borrowed motifs from both Roman and Near Eastern styles. From Near Eastern art, Christian and Jewish painters used the size of figures and primary colors to indicate their importance. Greek and Roman poses are adopted. Priests generally wear togas.

bucolic scene: The Good Shepherd with his flock in the paradise? He's holding a Pan's flute like Orfeus.