The Christian faith had one of its longest and hardest fights at Præneste to overcome the old Roman cult of Fortuna Primigenia. Christianity triumphed completely, and Præneste was so important a place, that it was made one of the six suburban bishoprics,[[3]] and from that time on there is more or less mention in the Papal records of the diocese of Præneste, or Penestrino as it began to be called.
In the fifth century A.D. there is mention of a gift to a church by Sixtus III, Pope from 432 to 440, of a certain possession in Prænestine territory called Marmorata,[[4]] which seems best located near the town of Genazzano.
About the year 970 the territory of Præneste was increased in extent by Pope John XIII, who ceded to his sister Stefania a territory that extended back into the mountains to Aqua alta near Subiaco, and as far as the Rivo lato near Genazzano, and to the west and north from the head of the Anio river to the Via Labicana.[[5]]
A few years later, in 998, because of some troubles, the domain of Præneste was very much diminished. This is of the greatest importance here, because the territory of the diocese in 998 corresponds almost exactly not only to the natural boundaries, but also, as will be shown later, to the ancient boundaries of her domain. The extent of this restricted territory was about five by six miles, and took in Zagarolo, Valmontone, Cave, Rocca di Cave, Capranica, Poli, and Gallicano.[[6]] These towns form a circle around Præneste and mark very nearly the ancient boundary. The towns of Valmontone, Cave, and Poli, however, although in a great degree dependent upon Præneste, were, I think, just outside her proper territorial domain.
In 1043, when Emilia, a descendant of the Stefania mentioned above, married Stefano di Colonna, Count of Tusculum, Præneste's territory seems to have been enlarged again to its former extent, because in 1080 at Emilia's death, Pope Gregory VII excommunicated the Colonna because they insisted upon retaining the Prænestine territory which had been given as a fief to Stefania, and which upon Emilia's death should have reverted to the Church.[[7]]
We get a glance again at the probable size of the Prænestine diocese in 1190, from the fact that the fortieth bishop of Præneste was Giovanni Anagnino de' Conti di Segni (1190-1196),[[8]] and this seems to imply a further extension of the diocese to the southeast down the Trerus (Sacco) valley.
Again, in 1300 after the papal destruction of Palestrina, the government of the city was turned over to Cardinal Ranieri, who was to hold the city and its castle (mons), the mountain and its territory. At this time the diocese comprised the land as far as Artena (Monte Fortino) and and Rocca Priora, one of the towns in the Alban Hills, and to Castrum Novum Tiburtinum, which may well be Corcolle.[[9]]
The natural limits of the ancient city proper can hardly be mistaken. The city included not only the arx and that portion of the southern slope of the mountain which was walled in, but also a level piece of fertile ground below the city, across the present Via degli Arconi. This piece of flat land has an area about six hundred yards square, the natural boundaries of which are: on the west, the deep bed of the watercourse spanned by the Ponte dei Sardoni; on the east, the cut over which is built the Ponte dell' Ospedalato, and on the south, the depression running parallel to the Via degli Arconi, and containing the modern road from S. Rocco to Cave.
From the natural limits of the town itself we now pass to what would seem to have been the extent of territory dependent upon her. The strongest argument of this discussion is based upon the natural configuration of the land. To the west, the domain of Præneste certainly followed those long fertile ridges accessible only from Præneste. First, and most important, it extended along the very wide ridge known as Le Tende and Le Colonnelle which stretches down toward Gallicano. Some distance above that town it splits, one half, under the name of Colle S. Rocco, running out to the point on which Gallicano is situated, and the other, as the Colle Caipoli, reaching farther out into the Campagna. Along and across this ridge ran several ancient roads.[[10]] With the combination of fertile ground well situated, in a position farthest away from all hostile attack, and a location not only in plain sight from the citadel of Præneste, but also between Præneste and her closest friend and ally, Tibur, it is certain that in this ridge we have one of the most favored and valuable of Præneste's possessions, and quite as certain that Gallicano, probably the ancient Pedum,[[11]] was one of the towns which were dependent allies of Præneste. It was along this ridge too that probably the earlier, and certainly the more intimate communication between Præneste and Tibur passed, for of the three possible routes, this was both the nearest and safest.[[12]]
