is rationem: non sicut Aius.. ita Vaticanus deus nominatus
penes quem essent vocis humanae initia . .), who gives two current
explanations of the name.
It is probable that the adjective form, Vaticanus, is derived from
some substantive, perhaps Vaticanum (Elter, see below), or from the early
Etruscan name of some settlement, like Vatica or Vaticum (Niebuhr), of
which all other traces have vanished, except possibly the cognomen
Vaticanus which is found twice in the consular Fasti in 455 and 451 B.C.
(RE i. A. 1071 ; BC 1908, 23-26).
(2) VATICANI MONTES
without much doubt a general designation for
the hills in the ager Vaticanus, but used, in its only occurrence in litera-
ture, of the long ridge from the Janiculum to the modern Monte Mario
(Cic. ad Att. xiii. 33. 4: a ponte Milvio Tiberim duci sccundum montes
Vaticanos, campum Martium coacdificari, illum autem campus Vaticanum fieri quasi Martium campum). Here campus Vaticanus must
be used of the whole district between Monte Ma