The altar, which is presumed to be dedicated to Saint Anthony, does not exhibit the recurring 17th-century decorative layout found in the other altars of the church.

The fragment of fresco on the same wall depicts a scholar: the absence of a halo framing the face supports the hypothesis that it is not a saint or a blessed figure, but an influential prelate of the time, belonging to the Dominican order.

Just below, an engraving made with a sharp object on the plaster can be seen. It appears to be a boat with a sail, presumably made by a fisherman following a received grace. A similar engraving is visible in the presbytery area.