Premise: Steep stairs to the right of the main entrance lead to the small Museo Marciano, where you can see the original four tethered bronze horses, dating from the 2nd or 3rd century a.d. and a privileged close-up of the basilica's mosaic ceilings from the museum's open galleries.

Hypothesis: The four tethered bronze horses can be seen in the small Museo Marciano.
Relation: entailment