Take the tour on this website and describe three pieces in the art collection of the early cities. (site 1)

The gregorian chant was a major cultural milestone in the middle ages. it was one of the first codified forms of music meant to be played as written, where previously it was difficult to mass-produce and disseminate any music. what's more, these chants were also some of the first examples of musical notation: the notes and bars of today's music sheets are a reflection of centuries of evolution beginning with these chants. it became official throughout the entirety of the catholic church, meaning that nearly all of europe followed this musical notation and styling.

The right answer for the question that is being asked and shown above is that: "b. middle byzantine"this painting entitled, the old testament trinity, is an example of  middle byzantine  art.  middle byzantine arts are mostly religious related ones that depicts the faith of christianity.