Churches of Rome Wiki

San Tommaso in Formis is a 13th century convent church, at Via di San Paolo della Croce 10 on the top of the Caelian hill next to the Arch of Dolabella. This is in the rione Celio, part of the historic rione Campitelli. Pictures of the church at Wikimedia Commons are here. There is an English Wikipedia page here.

The dedication is to St Thomas the Apostle.


The arch[]

The gateway to the church is next to what is now called the Arco di Dolabella, which was almost certainly the Porta Caelimontana ("Caelian Hill Gate") in the original city wall -the Servian Wall. This is not to be confused with the present walls, which enclosed a much larger area. The gate here was erected in the year 10 AD, as recorded in the dedication inscription above it. This is illegible now, but used to read:

P[ublius] Cornelius P[ublii] f[ilius] Dolabella [et] C[aius] Iunius C[aii] f[ilius] Silvanus, flamen Martial[is], co[n]s[ules], ex s[enauts] c[onsulto] faciundum curaverunt, idem probaverunt.

The year is given by the fact that these two were consuls then.

The Emperor Nero used the gate when he built a branch aqueduct from the Aqua Claudia to the nymphaeum of his Domus Aurea, and this branch later served as the water supply for the imperial palace on the Palatine. When the aqueduct collapsed, this arch was kept because part of the convent was extended over it. The name formis is from the Latin fornix, "arch".

Tommaso in Formis

The church entrance is to the right of the arch.


Why the church was founded is a mystery, since it only appears in history at the start of the 13th century. At this point it belonged to a Benedictine monastery, so there are two likely original alternatives.

Firstly, the monastery was originally founded by Byzantine-rite refugees from the Iconoclast policies of the Byzantine Empire in the late 7th or 8th century -Roman monasticism at this period was mostly Greek (a fact that was maliciously deleted from the historical record in the later Middle Ages).

Alternatively, it was founded by the Benedictines when they actually established a major presence in Rome, around the start of the 10th century (they then pretended that they had been at Rome since the 6th century, which is simple falsehood). There is no way of telling which of these alternatives is correct.


The Benedictines had twenty monasteries in Rome in the early 12th century, including this one.

However, Benedictine monastic observance in Rome collapsed completely by the latter part of that century. In fact, the life that most monks led was so corrupt that they were little better than religious vermin pretending to belong to the nobility, and in response the Church dispossessed them (except for San Paolo fuori le Mura). Here, the monastery was given to St John of Matha by Pope Innocent III in 1209. He was French, and one of the founders of the Trinitarian Order for the ransoming of Christians enslaved by Muslims in Spain and North Africa. He had arrived in Rome to promote his work two years earlier.

The saint established the first seat of the new Order here. The church and convent were rebuilt, and the saint also added a hospital or hospice to the latter. This was for poor and sick people, and also for pilgrims and penniless redeemed captives. Back then the Clivus Scauri, the street passing under the arch was the main road from the Lateran to the river quays at the present Bocca della Verità and so would have seen a lot of traffic. Among the visitors was St Francis of Assisi, who prayed in this church.

St John died in the convent, and was initially buried in the church in 1213.

In 1217 Pope Honorius III gave the convent the right to collect tolls from those passing through the gateway, which must have put the finances of the hospital on a better footing (the Order always struggled with financial difficulties).


The Trinitarians left Rome in 1380, and abandoned the complex -taking the relics of St John to Spain. At first it was administered by a commendatory cardinal, but in 1395 possession was transferred to the Chapter of St Peter's (also known as the Vatican Chapter). The buildings seem to have been left derelict, and the church was closed down. The arms of the Vatican Chapter are found over the sacristy door.

Only in 1532 was the church restored, using materials from the ruined hospital, and in 1571 Pope St Pius V restored the church and the remains of the hospital to the Trinitarians. However the pope did not formalize the arrangement and, after his death, the Order had to relinquish possession to the Chapter again. 

Modern times[]

Although the church was useless pastorally, being surrounded by countryside with three other churches close by, the Chapter did maintain it in good repair.

The first restoration, almost amounting to a rebuilding, was in 1663 and the last by them was in 1787. The little convent, next to the archway, was repaired to serve as a priest's house. The remnants of the hospital, which had been a very large edifice of two wings, seem to have been left alone.  As a result of all this, little is left of the medieval structure, furnishings and decorations apart from the famous mosaic over the hospital gateway.

The Chapter ended up only arranging one Mass a year here, on the feast-day of St Thomas (which used to be 21 December). This state of affairs continued until the early 20th century, although the cell of St John was converted into a devotional chapel with an altar in 1864.

The Trinitarians were again granted formal possession of the church in 1898 with some rooms next to the gate, including the cell-chapel of St John which is actually over the arch. The Order took a while to restore the little complex, and only finished the church in 1925. It carried out another restoration in 2001.

The Church is also the National Chapel of "I Ragazzi del 99" (The Boys of 99), an organisation dedicated to the memory of those Italian young men born in 1899 who were part of the last class of conscripts called up for military service in 1917, at the height of Italy's involvement in the First World War.

Agricultural research centre[]

The Agricultural Experimental Station of Rome was founded in 1871, the year after Italy conquered Rome. It was partly in response to the hopeless state of the countryside around the city, ruined by centuries of importing cheap food for cash on the part of the Papal government. What was left was basically treeless short-grass prairie, dominated by poor-quality sheep and with the soil completely impoverished. The change since then has been astonishing.

The fertilizer problem led to a concentration on soil chemistry, for which the institution became famous. It is now the Centro di Ricerca per lo Studio delle Relazioni fra Pianta e Suolo, to indicate that there is more to soil than fertilizing it. It occupies the site of the old hospital, the remains of which were incorporated into a new building in 1925. 


Layout of complex[]

The original complex had three separate structures: church, convent and hospital. The church was all on its own in the north-west corner of the property, without any structure connecting it to the convent and on a different alignment to the hospital. This indicates that it was probably rebuilt in the 13th century on the footprint of the original church.

The little convent, with a tiny cloister, was next to the arch and occupied rooms over it. Here is the chapel of the cell of St John of Matha, although it has not been regularly accessible to visitors in recent years.

The hospital was very large, and consisted of two parallel wings separated by a narrow courtyard. The gateway with the mosaic gave entry to the latter. 

Remains of hospital[]

Fragments of the Trinitarian hospital remain, incorporated into the agricultural institute. The entrance façade is partially preserved; the gable end corresponds to the frontage of the north wing of the hospital. To its right is the former garden entrance, between the hospital and the convent.

The former main hospital entrance to the left has a fine arched Romanesque portal with a molded archivolt on Doric pillars, and above this is an arched aedicule with thin supporting columns. This protects a mosaic by the Cosmati family depicting Christ between Two Freed Slaves. Freeing slaves was one of the main tasks of the Trinitarians, and the mosaic depicts the Seal of the Order. One slave is white, and the other black. The work is signed by «Master Jacobus and his son Cosimatus», and dated 1218 -it is very well preserved, and can fool you into thinking that it is modern.

The Institute building displays some mediaeval fabric, but is private.

Church layout and fabric[]

This is a small church, basically a rectangular brick box with a pitched and tiled roof. There is a little semi-circular external apse, and on the roof gable above this is a tiny campanile with one bell. There are three large windows in each side wall, which replaced the original mediaeval windows in the 17th century restoration.

San Tommaso in Formis

The doorway next to the arch actually admits you to a pretty vicolo or path with walls and hedges on both sides, leading to the church itself. The façade is very straightforward and lacks decoration. There is a molded doorcase, a raised segmental pediment, a large rectangular window above this, four blind pilasters without capitals and a crowning triangular pediment with an empty tympanum. A short dedicatory inscription is above the door lintel, and to the right of the door is a plaque bearing the symbol of the Name of Christ -IHS, from the Greek IHΣYΣ. That's it.

To view the rest of the church exterior, you need to go into the Villa Celemontana park. The nearest entrance is on the other side of Santa Maria in Domnica.


Layout and fabric[]

San Tommaso

The simple rectangular interior demonstrates that the term "Baroque minimalism" is not an oxymoron. Apart from a pair of altars and three windows each high up, the side walls are entirely undecorated. The coved ceiling has shallow lunettes over the windows, and in the central panel is the coat-of-arms of the Trinitarian order. This has a cross formed of a vertical red bar over a horizontal blue one, and the crowned shield is surrounded by a chain and fetters.

The overall colour scheme is white and grey.


If you've looked at the exterior of the church already, you may be puzzled at the invisibility of the apse. This is because, in the 17th century restoration, the original sanctuary was walled off to create a sacristy. Beforehand, the church had nowhere to store vestments and liturgical items, or for the priests to vest. So, either side of the altar there is a doorway with a molded doorcase and a raised and slightly oversized segmental pediment on which a coat-of-arms is superimposed. Behind the pediments are internal windows helping to light the sacristy (which otherwise only has a little window over the apse).

The main altar is a large Baroque composition, with four fluted Corinthian columns in grey marble forming two pairs, the outer one set back. Over the inner pair only is a triangular pediment with modillions.

The altar is dedicated to St John of Matha (despite the dedication of the church), and the altarpiece features Christ Commissions St John of Matha by Aronne Del Vecchio.

The altar pro populo, installed for Mass celebrated facing the people, is on a pedestal bearing the Trinitarian cross. You can see this emblem in other Trinitarian churches in Rome, notably San Crisogono and San Carlo alle Quattro Fontane.

Side altars[]

The pair of side altars are almost identical. Each has a pair of Ionic columns in grey marble and with swagged capitals, and these support an arched entablature which curves over a large wreath. The frontal is revetted in red marble.

The left hand altar is dedicated to St Thomas. The altarpiece is anonymous, late 16th century, and depicts The Incredulity of St Thomas. The apostle is represented as inserting his finger in Christ's side.

The right hand altar is dedicated to Our Lady. The title under which she is venerated here is Santa Maria del Buon Rimedio, which is a special devotion of the Trinitarians. The modern altarpiece by Felice Casorati shows her giving a slave's ransom to St John; the detailing is very well done, especially the vase of flowers featured. The saint is wearing the Order's distinctive white habit.

In the centre of the frontal of this altar is enshrined a finger bone of St John of Matha.

Other paintings[]

Two other paintings of interest hang in the church. One is by by Girolamo Sicolante di Sermoneta, and shows the Madonna and Child being venerated by SS Francis of Assisi and Boniface of Rome, with Pope Boniface IX kneeling in the foreground.

The other one, by Del Vecchio, shows the approval of the Order's rule by Pope Innocent III.

There is a wall tablet commemorating the 1797 restoration, in an interesting Baroque shape unusual for that period.

Stained glass[]

To celebrate the 2000 Jubilee the Order commissioned seven stained glass windows from Samuele Pulcini, to commemorate holy people associated with it. Six are in the side walls, and one over the entrance. They feature:

St John of Matha.

St Felix of Valois, who was the other founder of the Order.

St John Baptist of the Conception (1561-1613). He was a Spanish reformer of the Order.

Teresa Cucchiari, the 18th century foundress of the Trinitarian nuns.

Giuseppe Di Donna (1901-52), a Trinitarian missionary and bishop whose beatification is in process.

BB Anna Maria Taigi and Elizabeth Canori Mora. The former was a holy Trastevere housewife who is enshrined in San Crisogono as an oblate of the Order. The latter was another Roman tertiary of the Order, who is enshrined at San Carlo alle Quattro Fontane.

The Madonna del Buon Rimedio.

Cella di San Giovanni di Matha[]

As mentioned above, the cell occupied by St John of Matha, one of the founders of the Trinitarians, is in the wing of the convent over the Arch of Dolabella. This was renovated as a presbytery for the church in 1787, and the cell seems to have been fitted (or re-fitted) as a chapel then, in a rather rich late Baroque style involving polychrome marble work.

The chapel is very small. It is entered through an arched portal in a thick load-bearing wall, the arch and its supporting piers being in a yellowish-white-in-grey brecciated marble. The archivolt springs from two pairs of longitudinal Tuscan Doric pilasters, which have a thin rectangular vertical panel of grey-veined yellow Siena marble inset into each face (eight in all, two facing out, two in and four facing each other).

The interior walls are revetted in the same brecciated marble. The flat ceiling is in white. The floor is in a yellow marble, with a deep red marble border. In front of the altar is a device representing the Trinity consisting of three interlaced circles in red, yellow and white marbles. The sanctuary platform, taking up much of the room, is in red marble inlaid with diaper square white tiles in a chequerboard pattern.

The altar is also in the grey and white brecciated marble. A pair of huge downwardly tapering strap corbels supports the mensa. In between is a panel of onyx on which is a cross in red marble.

Above the mensa is a shallow round-headed niche in vermillion red, in which a portrait in oils of the saint is hung.


This church used to be seldom open, usually only on Sunday morning for Mass. However, in recent years there seems to have been some effort to have it open for visitors during the week, too. If you are walking under the arch and see the side door open, do visit.

The Cella di San Giovanni di Matha must have some sort of access, because a photo of it has turned up on a blog page (see "External links"). If you find the church open and there is a custodian available, ask.


Mass is celebrated at 10:30 on Sundays and Solemnities, according to the Diocese and the notice on the church gateway.

As of March 2019, there was also a notice just outside the Arch of Dolabella, issued by the parish at the nearby Basilica of Santa Maria in Domnica, indicating a 19:00 weekday Mass at San Tommaso. (This may be due to the fact that works on Metro C are interfering with the liturgical activities of Santa Maria.)

The major feast of the church is that of St Thomas, on 3 July. St John of Matha is celebrated on 8 February.

The church has no pastoral justification (the parish church of Santa Maria in Domnica is within shouting distance), and the Order is to be commended for giving it loving attention.

You can get married in this church - if you are a Catholic. It is suitable for quiet weddings, with a fairly small number of guests.

External links[]

Official diocesan web-page

Italian Wikipedia page

Interactive Nolli Map Website

Blog page featuring cella

"De Alvariis" gallery on Flickr

Thayer's web-page

Info.roma web-page

Romeartlover web-page