It is to be noted that this Marcigliana road was not to tap the trade route along the Volscian side of the Liris-Trerus valley, which ran under Artena and through Valmontone. It did not reach so far. It was meant rather as a threat to that route.
Whether these towns are Pedum or Bola, Scaptia, and Querquetula is not a question here at all.
Gatti, in Not. d. Scavi, 1903, p. 576, in connection with the Arlenius inscription, found on the site of the new Forum below Præneste in 1903, which mentions Ad Duas Casas as confinium territorio Prænestinæ, thought that it was possible to identify this place with a fundus and possessio Duas Casas below Tibur under Monte Gennaro, and thus to extend the domain of Præneste that far, but as Huelsen saw (Mitth. des k.d. Arch, Inst., 19 (1904), p. 150), that is manifestly impossible, doubly so from the modern analogies which he quotes (l.c., note 2) from the Dizionario dei Comuni d'Italia.
It might be objected that because Pietro Colonna in 1092 A.D. assaulted and took Cave as his first step in his revolt against Clement III (Cecconi, Storia di Palestrina, p. 240), that Cave was at that time a dependency of Præneste. But it has been shown that Præneste's diocesan territory expanded and shrunk very much at different times, and that in general the extent of a diocese, when larger, depends on principles which ancient topography will not allow. And too it can as well be said that Pietro Colonna was paying up ancient grudge against Cave, and certainly also he realized that of all the towns near Præneste, Cave was strategically the best from which to attack, and this most certainly shows that in ancient times such natural barriers between the two must have been practically impassable.