The elegant Romanesque façade has the appearance of a wall, with a central door, embellished in the 15th century, and two smaller flanking doors; each door is a round arch set into a series of archivolts, and each is surmounted by a rose window.
The main decoration of the façade, however, consists in the use of contrasting stone arranged in a sort of tapestry of cruciform elements.
The façade lacks any of the customary crowning gables or other superstructures and may be unfinished.
An octagonal belfry, reduced to a stub after it had to be demolished following an earthquake, gives the building an asymmetrical appearance.
The three portals and three rose-windows are all different.
The central door was significantly reworked in the 15th century, decorated with blank niches arranged in two rows over a base composed of square panels carved with floral motifs.

A rear view of the church shows a congeries of various extensions over the centuries, mostly of the Gothic period.

The interior follows the standard plan of a nave and two side aisles, each one divided from it by a row of columns, from which arches support a tall wooden ceiling.
The floor of the nave is in the same red and white stone as the façade.

A major restoration, aiming to return the church to its original Romanesque appearance by removing accretions over the centuries, was completed in 1972.
This was the first time its furniture was actually refurbished.

The church's principal monument, in the right aisle next to the choir, is the tomb of pope Celestine V. Commissioned by a guild of wool workers in 1517, it is the work of Girolamo da Vicenza, and contains the remains of the Pope in a silver urn.
The present urn was made at the end of the Second World War by Aquilan goldsmith Luigi Cardilli: it replaced an urn stolen by French troops in 1646, which itself replaced the first urn, removed by the Prince of Orange in 1530.
The transept also includes two Baroque altarpieces, one of which includes a 14th-century statue of the Virgin, often attributed to Silvestro dell'Aquila, a pupil of Donatello.

The interior of the church is not profusely decorated, or at least not much decoration has come down to us, but includes 14th- and 15th-century frescoes by an anonymous local artist, depicting scenes of the Virgin's life: the Virgin Mary between St. Agnes and St. Apollonia, a Dormition of the Virgin, and a Coronation.
The church also contains a Crucifixion with St. Julian (who is specially venerated in L'Aquila), an early 16th-century frescoed niche of a Virgin with Child and Saints, and fourteen oversized 17th-century paintings by Karl Ruther, a monk of Gdańsk, representing episodes from the life of St. Celestine.
The elegant Romanesque façade has the appearance of a wall, with a central door, embellished in the 15th century, and two smaller flanking doors; each door is a round arch set into a series of archivolts, and each is surmounted by a rose window. The main decoration of the façade, however, consists in the use of contrasting stone arranged in a sort of tapestry of cruciform elements. The façade lacks any of the customary crowning gables or other superstructures and may be unfinished. An octagonal belfry, reduced to a stub after it had to be demolished following an earthquake, gives the building an asymmetrical appearance. The three portals and three rose-windows are all different. The central door was significantly reworked in the 15th century, decorated with blank niches arranged in two rows over a base composed of square panels carved with floral motifs.
A rear view of the church shows a congeries of various extensions over the centuries, mostly of the Gothic period.
The interior follows the standard plan of a nave and two side aisles, each one divided from it by a row of columns, from which arches support a tall wooden ceiling. The floor of the nave is in the same red and white stone as the façade.
A major restoration, aiming to return the church to its original Romanesque appearance by removing accretions over the centuries, was completed in 1972. This was the first time its furniture was actually refurbished.
The church's principal monument, in the right aisle next to the choir, is the tomb of pope Celestine V. Commissioned by a guild of wool workers in 1517, it is the work of Girolamo da Vicenza, and contains the remains of the Pope in a silver urn. The present urn was made at the end of the Second World War by Aquilan goldsmith Luigi Cardilli: it replaced an urn stolen by French troops in 1646, which itself replaced the first urn, removed by the Prince of Orange in 1530. The transept also includes two Baroque altarpieces, one of which includes a 14th-century statue of the Virgin, often attributed to Silvestro dell'Aquila, a pupil of Donatello.
The interior of the church is not profusely decorated, or at least not much decoration has come down to us, but includes 14th- and 15th-century frescoes by an anonymous local artist, depicting scenes of the Virgin's life: the Virgin Mary between St. Agnes and St. Apollonia, a Dormition of the Virgin, and a Coronation. The church also contains a Crucifixion with St. Julian (who is specially venerated in L'Aquila), an early 16th-century frescoed niche of a Virgin with Child and Saints, and fourteen oversized 17th-century paintings by Karl Ruther, a monk of Gdańsk, representing episodes from the life of St. Celestine.
Santa Maria di Collemaggio