From the second half of the 16th century, it has a single nave with small crypt. The restoration work of the Church of Santa Croce carried out in the nineties brought to light on the back wall a fresco, attributed to the youthful production of Giovanni Battista Lombardelli (1537 ca. – 1592), a painter from the Marches who worked since 1574 in Ostra Vetere and Serra de’ Conti, where he stayed for a few years before moving to Perugia, Rome and Loreto, being called up by various commissions.
...In the lateral pilasters painted with two false niches are depicted the prophets David and Isaiah (?), who introduce to the main scene dedicated to the Legend of the True Cross. In the center is represented the Cross raised on Golgotha after the discovery by the empress Elena, below the miracle of the young man resurrected from the S. Cross. The composition is dominated by a cymasis with Christ crucified and angels holding up the symbols of the passion. In the right wall was placed a group of frescoes attributed to Pier Paolo Agabiti, painter and architect native of Sassoferrato, whose presence in Serra De’ Conti is documented in the second decade of the 16th century. The work was originally placed in the former medieval municipal prisons and was then moved, recently, to the hall of the city council (in the old building of Palazzo Palazzi). The work is divided into three panels: in the central one is a Madonna on a throne with Child; at the sides are recognizable the Blessed Gherardo, patron of Serra De’ Conti, and a figure of saint, perhaps attributable to San Fortunato. In the left panel is a lion with the banner containing the sixteenth-century emblem of the municipality, while in the right panel there is an allegorical representation of Justice.