Domitian's nymphaeum was incorporated into the fortified system of the II Parthian Legion and is certainly the most representative and refined buildng in the military complex planned by Septimius Severus. Saved from demolition by the Roman legionaries because of its size and magnificance, the nymphaeum was utilised as a bathhouse by the same legionaries after a substantial renovation and conversion to its new purpose. Square in plan view but circular on the inside with spherical sections it is covered by a cupola with a skylight at the centre and is furnished with four niches which contain an equal number of fountains. At the entrance it is possible to see the mosaic flooring from the Severan period depicting sea monsters. On the inside there is a wave motif which leads into the central tub.
Its orientation determined the subsequent plan and orientation of the encampment which thus had its sides parallel to those of the nymphaeum and also to the existing terraces of the Roma villa in whose grounds it was built. This caused it to be at an oblique angle with respect to the Via Appia.. Hypocausts and connecting corridors were added in its conversion to its new function which was certainly continued right up to the time of Constantine, when the legionaries were then moved to new bases. The transformation of the baths into a Christian church probably took place in the VIII cent. under Stephen III (Galieti p.157) while the first substantial architectural changes go back to the Middle Ages, before the consecration of 1060. More alterations was carried out for the new consecration in 1316, consisting in the removal of the medieval apse and more recently, alterations were carried out in XVIII and XIX centuries. The most ancient document regarding the church is the letter of Celestino III dated 16 December 1195. In the 14th century Augustinian monks were the owners of the church but with their abandonment of it in 1444 it was assigned to the Girolamini monks by Eugenio IV (Galieti p.174). It was they who, in the early 1600's, restored the "ruined" church and at the same time definitively changing its appearance. Between 1703 and 1799 the bell tower was restored; other works and accretions all reflecting the style of the 19th cent. systematically altered the classical facade of the building. Finally in 1938 the architect Terenzio who was superintendent of the monuments in the Lazio region, completed the work of restoration and cleaning of the Roman hot room of the numerous additions of successive centuries, bringing the level of the floor down to the original level, which had been buried beneath 3.30 m of infilling and various layers of flooring, bringing back the refined brickwork and most of all, recovering the ancient sense of space inside the building. The Nymphaeum of the Rotonda, having been returned to its original state after 2,000 years, is by now completely involved in the history of human habitation by its use and symbolic value. Past generations have passed on to us a glimpse of these values as can be seen in the small piazza outside. We would like to capture and preserve this in our own century, surveying and drawing it for the generations to come.
On the death of Septimius Severus and the succession of his two sons, Caracalla and Geta, the soldiers of the II Parthian Legion swore their loyalty to the heirs designate as the dead ermperor had wanted. But even before his death, in the preceding years, Caracalla, who had been elevated to the position Augustus by his father, had shown himself to be reluctant to share power. After the murder of Geta by Caracalla, the ranks of the army closest to the dead Septimius Severus, the Praetorian cohorts, the urban militia and the legion from Albano, saw the impossibility of keeping their promise of obedience and loyalty to the two sons. Reluctant to serve a fratricidal ruler, the legionaries of the II Parthian Legion slammed the gates of their garrison shut and and occupied themselves in its defence, refusing out of hand to obey Caracalla. The Life of Geta outlines the opposition of the military in Rome and in Albano where the emperor forthwith arrived, and from beneath the walls made no small effort in trying to convince the soldiers to accept his imperial status, justifiying himself with presumed crimes committed by Geta and promising huge increases in their pay (up to 1,250 attic drachmas as against 720 in the period under Augustus). Amongst the gifts conceded to the soldiers of Albano, in addition to a bounty of 2,500 attic drachmas, were new and large buildings constructed for the pleasure and well being of the soldiers, along with the rest of the community of the encampment. The great baths located on the outskirts of the encampment became a new service complex replacing the much more modest baths of the military camp. Thus the baths came to be constructed on the hill under the Via Appia. They were set at an angle to it in order to catch as much light and warmth for the heated rooms and to which end extensive windows were also created. One could enjoy beautiful views from every level, looking towards the plain underneath Mount Albano, running all the way to the Tyhrennian Sea and Monte Circeo. The grand elegant style is evocative of the refined works of Sesto Giulio Africano, the architect of the Severi, who worked on the most important baths in Rome up to the time of Severus Alessandro (Calderini p.456). The water supply was ensured by means of an aqueduct which crossed the Via Appia over an arch which physically linked the encampment to the baths. This type of connection which was constructed after the encampment itself, shows clearly that in reality the military presence in Albano had progressively lost its fortified defensive nature.
In fact both the construction of the Baths and that of the Amphitheatre quickly ensured the transformation of the encampment from a military garrison, isolated and defensible on all sides, to that of a barracks both logistical and operational. It was equipped with civil structures, put in dominating positions with respect to the camp, and thus places of easy access in the event of possible attack. The construction of the Baths and the Amphitheatre behind the encampment evidence a new military function for the II Parthian Legion. Already, during the last years of the reign of Septimius Severus, the important transformation of the military picture, with the elevation of all the centurions of the rank of Knight, the possibility for soldiers to wear the golden ring, likewise the recruitment of "provincials" into the ranks of the elite guards and the militarization of the major offices of state, all delineate a growing decadence and a weakening of the ancient republican structure of the aristocratic senatorial classes.
Decorated with plaster, richly provided with mirrors and marble statues, the baths included numerous other services: libraries to study in, reading rooms, spaces to relax. We don't presently know the precise purposes and uses of the various spaces and areas so magnificently passed to on to us; nevertheless the polychrome mosaic floor of the intermediate floor, (partly visible in the sacristy of S.Pietro), underlines the refinement of the craftsmen that worked on the structure, shoulder to shoulder with the soldiers of the legion who certainly did the bulk of the work.
In the imperial period the baths became the place of recreation par exellence, even if the characteristic of the Roman bath consisted in the cold open air pool. For a Roman, the indoor pool was a necessary concession for technical reasons, that should however, be completed, weather permitting, with a dip in the outdoor pool surrounded by a natural backdrop full of flowers, ornamental pots and plants. The interior often depicted the same naturalistic scenes as were present outside, in the manner of Manlio Vopisco at Tivoli (Grimal p.196). The paintings, which often included architectural designs or structures in an allusive manner, depicted landscapes, gardens and muses. In their turn, the gardening themes invaded the insides of the baths with floral designs which together with the frescoes, appeared like the natural surroundings of the 'cold bath' outside. The connection between artifice and and nature was characteristic of 'Roman naturalism;' taking numerous everyday objects it depicted them in a context that made them appear like parts of nature. The running of the thermal baths which were free, was entrusted to specialised personnel, who in addition to ensuring that the temperature was correctly maintained, the ventilation controlled and the flow of water, offered various services including massage, anointing, perfuming and gymnastic exercises.
The three fundamental phases of the bath were controlled according to medical and hygenic principles: a hot room to open the pores and cause free sweating, washing and baths in hot water, and then after a period for thermal readjustment, the bath in the cold pool with swimming and diving activities (Staccioli p.32). This cycle could be repeated several times. Very often the system of bathing called bagno laconico was preferred, which based based on the alternation of hot and cold baths, or sometimes heated baths with medicinal or curative substances added were used.
With the departure of the II Parthian Legion from Albano, the definitive disbanding of the Praetorian Cohorts and the urban troops of the capital, and most of all with the progressive abandonment of the capital by the emperors of the IV cent., a period of imperial decline started in the West, while the rapid impoverishment of the city led to the depopulation of the area. The same fate followed at Albano, where the great service structures of the legion: the baths, the amphitheatre, the aquaducts, all underwent a progressive decline through lack of maintenance.
The fate of the Terme di Cellomaio was thus one of decline, in common with all the other great structures of the imperial period. Nevertheless daily life inside this great ruins never completely ceased. The large amount of archeological and documentary evidence all indicates widespread inhabitation of these sites, from the Donation of Constantine to the christian community at Albano up to the present day (Liber Pontificalis, I, p. CLI). From the beginning of the 4th cent. to today, the remains of the baths have been used not just for residential purposes; in fact already in the 6th cent., according to Giorni, a great rectangular hall was transformed by Pope Ormisda: fecit basilicam in territorio albanense, possessine Mefontis (anni 514-523) ornata di portici, verisimilmente in facciata a racchiudere il natece (Galieti p. 121). The church was dedicated to Saint Peter, it was restored later by Leone III (795-816). From 14 February 1735 a large part of the baths was occupied by the Conservatorio delle Zitelle della signorina Maria Maggiori, which is now the Conservatorio delle Suore Oblate di Gesu e Maria; it was donated by a benefactor Pietro Paolo Mavillo, (State Archives RCA act Conti a. 1735) who "had built a new palace for his use, in the ancient baths of the Celio Mario on a site acquired by him and sold by the R.C.Apostolica ......in the year 1732."
In 1735 the new church was finished "on the site on which it is seen today among the ruins of the ancient Cellomaio, with a sacristy and two other rooms," adjacent to the conservatory of the Oblate Sisters; on this site today there still exists a nursery school, gardens, a refectory and meals for children, all housed in the evocative site of the ancient baths. The part of the baths that look eastwards, today belongs to Alfonso Pacetti, a citizen of Albano and great 'afficionado' of all things to do with Albano. It is he who has provided for the rennovation of the houses and rooms of his property through the work of engineers and architects Maggi and Maroni, putting the ancient medieval lodgings back into good condition and recovering areas which had been buried for centuries. These two specialists have worked also on the property of the Sisters, where a consolidation of the structures facing west has been carried out, to say nothing of putting the outside areas and gardens in order for the purposes of use as a garden for children. Fortunately the present day neighbourhood of the Cellomaio has been protected from the ravages of modern building construction largely thanks to its location and status as an antique monument. In the lanes and vennels of the centre of Alabano, a web of craft activities and antique dealing has developed which has culminated in the creation of an antiques market which takes as its motto " in the footsteps of the past"; since April 1991 this has welcomed the thousands of visitors on Sundays, who respectfully invade the lanes around the ancient baths in the same spirit that their historical forebears did, with the will to socialise and chat to friends. Still today, at a corner or the ancient baths of the Cellomaio, perhaps a little run down by now, people continue to meet, argue and discuss the matters of the day.