Santa Francesca Romana church was built in the second half of the 10th century, incorporating an 8th-century oratory that Pope Paul I excavated in the wing of the portico of the Temple of Venus and Roma. It was rebuilt by Pope Honorius III in the 13th century, when the campanile was built and the apse was decorated with mosaics of a Maestà, the Madonna enthroned accompanied by saints. The interior has been altered since. Since 1352 the church has been in the care of the Olivetans. In the 16th century, the church was rededicated to Frances of Rome, who was canonized in 1608 and whose relics are in the crypt. Its travertine porch and façade is by Carlo Lambardi, and was completed in 1615.
The interior, a single nave with side chapels, was rebuilt by Lombardi beginning in 1595. In the middle of the nave is the rectangular schola cantorum of the old church, covered in Cosmatesque mosaics. Another prominent feature is the confessional designed by Gian Lorenzo Bernini (1638-49), in polychrome marbles with four columns veneered in jasper.
The church houses the precious Madonna Glycophilousa ('Our Lady of Tenderness'), an early 5th-century Hodegetria icon brought from Santa Maria Antiqua. The twelfth-century Madonna and Child that had been painted over it was meticulously detached from the panel in 1950, and is now kept in the sacristy.
The ancient oratory on which the current church was built was located by Pope Paul I on the place in which Simon Magus died. According to this legend, Simon Magus wanted to prove his powers as stronger than those of the apostles, and started levitating in front of Sts. Peter and Paul. The two apostles fell on their knees preaching, and Simon fell, dying. The basalt stones where the apostles were imprinted by the knees of the two apostles and are embedded in the wall of the south transept.
The tomb of Pope Gregory XI, who returned the papacy to Rome from Avignon, reconstructed to a design by Per Paulo Olivieri (signed and dated 1584) is in the south transept.
References:Sigmaringen Castle was first mentioned in the year 1077 in the chronicles of Petershausen monastery. The oldest parts of the castle are concealed beneath the alterations made during the 17th and the 19th centuries. The secret of the earliest settlement built on this defendable rock will never be fully revealed: large-scale excavation work would be necessary, which the extensive land development renders impossible. Judging from the many Roman remains unearthed in the area around Sigmaringen, the 12th century keep known as the 'Roman Tower' could be traced back to a Roman predecessor.
The castle remains that have been preserved (gate, great hall and keep) date back to the Staufer period around 1200. The castle remains were integrated into subsequent buildings. The foundations of the castle buildings are to a large extent identical to the surrounding castle wall.
These remains give us a good idea of how the castle might have looked during the 12th century.