This itinerary takes you to places where you can see the art of some of the most amazing artists in Italy, and most places are free, since they are churches, the only fee you pay is to turn the light on for a few minutes.
You don't have to go to all of the places, but it's worth it. The alternative is spending the whole day in the Vatican Museum or some other Museum.
And that is actually an option, you could break up the itinerary in two days, doing the part across the river on a separate day, starting with the Vatican museum really early and the rest in the afternoon.
Below you will find a brief explanation of who these artists are or where some of their works are. There are more, many more artists, but it would take 4 years of art history classes (which I failed in school) to cover them all. So you get the highlights. But these are worth it!
Michelangelo Buonarroti, (born in 1475, Caprese, [Italy]—died in 1564, Rome), Italian Renaissance sculptor, painter, architect, and poet who exerted an unparalleled influence on the development of Western art. He was a master at depicting the body with such technical accuracy that marble was seemingly transformed into flesh and bone. Michelangelo's influence on other artists was profound and has continued from Raphael in his time to Rubens, through to Bernini, and the last great sculptor to follow his tradition of realism, Rodin.
For more information go to: https://www.britannica.com/biography/Michelangelo