SANTA MARIA IN INSULA
The crypt of the abbot Epifanio

Plan of the primitive abbatial centre.
The place where the crypt of Epifanio is situated is in yellow.
The church of Santa Maria in Insula, according to the confirmed news of the Chronicon Vulturnense, was built (or anyway entirely restructured) on behalf of Epifanio, who was abbot of San Vincenzo between 824 and 842. So, the advanced suppositions are surpassed definitely before the systematic excavations of the whole monastic area have started, when people still thought that the centre of San Vincenzo had placed in the area of the present abbatial building, on the other side of  Volturno riverbed, until the 8th century.
Anyway, the church of Epifanio, whatever its name was, was formed by a rectangular-plan, elevated body, ending in the bottom with an high clover-shape presbytery, where the altar was placed. The floor, whose we don’t have traces, developed at a partially filled in level and communicated, through a variously articulated bay, with the basements of the contiguous church (the original San Vincenzo) and successively with the zone in front of the large refectory.
At the epoch of Epifanio, the contiguous church had been demolished and transformed into palace, using partly the basemental structures of the pre-existing building, partly adding a series of partition-bearing walls. It had to be surely a residential part reserved to distinguished guests and there is no doubt that the particular proximity to the crypt, as well as the presence of a series of building elements looking like a link-staircase between the inhabited floors and the underground ambulatory, induce to think that the purchaser of these articulated routes cared about the need of a straight link of this building with the environment where the frescoes are placed. Moreover, the ambulatory reached, through a light-slope route, an area reserved specifically to the guests, constituted of a yard with peristyle and masonry depth enriched by a perspective reproducing, like in the ancient Pompeian houses, the external, rural environment which wasn’t materially visible.
Going on, the route (which for the described part was entirely underground) lightened when it reached the zone anticipating the large refectory and through which all the religious people of the abbey had to pass necessarily and daily. Obviously, considering the described itinerary on the contrary, we deduce that the crypt was reachable easily, either by famous guests, religious people and occasional guests of the abbey, through a route initially luminous, then, excluding all the buildings developing above it, progressively became darker and darker as far as the crypt, where the importance of the source of light, constituted of a little lateral window (we will talk about it later), was remarkable.
The ambulatory, slipping in other buildings not yet excavated, from the refectory reached the lower part of the big church of San Vincenzo Maggiore, which, in this way, could be passed through a very large route coming out on the opposite side, on the Southern lateral façade, of the big cloister area and the workrooms. So, dating back to the epoch of Epifanio, we find out in the monastery a whole organisation; in fact, taking into account the big transformations acted by Giosuè at the beginning of the 9th century, the part of the monastery originally occupied by the first centre of San Vincenzo (which with the realization of the big church of Giosuè had become pratically not much representative for the official liturgical ceremonies), was dedicated to distinguished guests and the abbot residence.
The function of the church of Santa Maria in Insula can be guessed by the presence of a large number of burials recently found out ahead its façade, used also by strangers to the Abbey monastic life. Through the archaeological study, we didn’t find out sufficient elements to affirm the existence of a direct link between the external and inner sepulchral area, but neither how the above part of the presbytery communicated with the lower part of the church is clear. Probably, you could enter into the presbytery, remarkably elevated respect to the only nave level, through a straight staircase, perfectly axial with it. The circumstance that the church and consequently the crypt, is the ending environment of a long and articulated route, is sufficient to understand that it was a precise point of reference for whoever lived in the abbey, whatever was the reason, and that Epifanio had whished its realization in order to be frequented by more people, at least until he was alive.
The crypt plan is characterised to be formed by a rectangular-shape, transversal body that is an anomalous transept on which, in the centre, on a side joins a marked apsidal cavity and on the other one a very deep, rectangular indentation containing the little window through which you can observe the basements of the external church (n.2 in the plan). The function of this little window is not completely clear; in fact, however the conformation of the church nave is, it couldn’t illuminate sufficiently the underground environment, especially considering that it should have been found below the staircase of the presbytery above. Yet, at the present time, at any hour of the day, though the overall external conditions have changed because of the disappearance of the church wall-covering, the light penetrating through a little opening is a proper luminous axis directed towards the most internal part of the apse, illuminating directly the angel at the centre and at the same time creating a grazing band illuminating particularly the central Christ. So, it is clear it has an important function, though apparently secondary respect to the strongest illumination of the lateral little window (n.1 in the plan), in the light architecture sphere, which is a decisive element to understand the paintings cycle. It could be also a “fenestella confessionis”, even if there is a high difference between the crypt and the external level looking as if its practice utilization is impossible or difficult. However, the function of the walled arch readable evidently on the external face of the environment, level with the described central little window, is still unclear. The fact that the inner fillet doesn’t present any plaster signs let us understand that it has never had a function of communication with the church hall. It could be an arch with prevalently structural functions, though it is closely linked with the wall separator, but in this case its realization should have happened contextually to the external masonry. While, it could be more plausible the hypothesis that this arch has been realized in anticipation of the subsequent, foreseen execution of the frescoes, that is, being necessary a good illumination to realize most of the paintings, a large opening had been set in order to obtain the maximum of light during the workings and then that part have been walled up just when the Annunciation scene was painted and the staircase realized.
The only definitive (or prevalent) source of light, should have been, like it was happened, an other little window, set on the long arm bottom opposite to the entrance, whose higher arch shows a representation of an hand extended and directed towards the interior.
Two little niches face each other on the long walls, still on the opposite side of the entrance. On the apsidal structure there is a pseudo-dome linking up to the part below with no continuity solution.
(The text is drawn by: Franco Valente - San Vincenzo al Volturno. Architettura ed arte. Abbazia di Montecassino Editions 1995).