Why go
The cathedral is a good place to compare sculpture made for memory, devotion and display. Tino di Camaino's monument to Cardinal Petroni stages a deathbed scene above a raised sarcophagus. At the Piccolomini altar, figures by the young Michelangelo belong to a later artistic moment. These works are easier to appreciate when viewed as parts of the church rather than names on a checklist.
The full story
Look for the monument to Cardinal Riccardo Petroni in the left transept. Tino di Camaino made it in the early fourteenth century, raising the sarcophagus on carved supports and placing a curtained scene of the cardinal's death above. The arrangement turns a memorial into a sequence that asks the viewer to look upward. Nearby, a bronze tomb slab made by Donatello uses shallow relief to suggest the body of a bishop lying in a recessed space. Its effect changes when viewed from an angle. A later comparison is the Piccolomini altar near the entrance to the library. Several saints in its lower niches were carved by the young Michelangelo in the early sixteenth century. These works do different jobs, from remembering the dead to presenting holy figures for devotion, yet all depend on where a visitor stands. Walk around the interior with those shifts of viewpoint in mind. Some famous works formerly in the cathedral have moved to other collections, so focus here on the pieces you can identify in the church itself.