The static, iconographic art of the Eastern Roman Empire dominated Italian art in the early Dark Ages
Artistic expression in Dark Ages and early medieval Italy was largely church-related. Mass was recited in Latin, so to try and help explain the most important lessons to the illiterate masses, Biblical bas reliefs around the churches' main doors, and wall paintings and altarpieces inside, told key tales to inspire faith in God and fear of sin (Last Judgements were favorites).
Otherwise, decoration was spare, and what little existed was often destroyed, replaced, or covered over the centuries as tastes changed and cathedrals were remodeled.
Although the eastern Byzantine Empire, based from the Eastern church’s Constantinople, was confined politically to Italy’s northeastern Adriatic coast, the static and stylized iconographic tradition of its mosaics and, to a lesser degree, panel paintings carried over into most of the mosaic and painting throughout Italy starting from Ravenna in the 5C, and later Venice.
Byzantine painting is characterized by gold leaf backgrounds, its figures' faces (and eyes) were almond-shaped with pointy little chins. Noses were long with a spoon-like depression at the top, and the folds in robes (always Virgin Mary blue over red) were represented by stylized cross-hatching in gold leaf.
Overall, Byzantine art has a flattened look—due to an almost complete lack of perspective or foreshortening)—and and an oriental decorativeness and severely static rule that ensured the reproduction of icons that wavered little from past models, and it kept Italian painting moribund for over 800 years.
Painting didn’t break out of the conservative funk until the late 13th century when the International Gothic style finally shook things up.
Examples of Romanesque art in Italy
* Ravenna. The churches of Italy's Byzantine capital are covered in stylized Byzantine mosaics, especially at San Vitale and both Sant'Appolinare in Classe and Sant'Appolinare Nuovo.
* San Marco, Venice. Venice's cathedral is a late Byzantine church of domes and an astounding number of mosaics (while the overall effect is indeed Byzantine, many of the mosaics are of various later dates).
* Monreale Cathedral, Sicily. This hillside hamlet above Palermo houses a outsized cathedral swathed with Byzantine mosaics inside, its cloister columns topped with some of the most wonderful Romanesque carved capitals in Italy.