No one who has ever stood on the Janiculum, and looked down on the
river and the city, and across the Latin plain to the Alban mountain
and the long line of hills--the last spurs of the Apennines--enclosing
the plain to the north, can fail to realise that _Rome was originally
an outpost of the Latins_, her kinsmen and confederates, against the
powerful and uncanny Etruscan race who dwelt in the undulating hill
country to the north. The site was an outpost, because the three
isolated hills make it a natural point of defence, and of attack
towards the north if attack were desirable; no such point of similar
vantage is to be found lower down the river, and if the city had been
placed higher up, Latium would have been left open to attack,--the
three hills would have been left open to the enemy to gain a firm
footing on Latin soil. It was also, as it turned out, an admirable
base of operations for carrying on war in the long and narrow
peninsula, so awkward, as Hannibal found to his cost, for working out
a definite plan of conquest. From Rome, astride of the Tiber, armies
could operate on "interior lines" against any combination--could
strike north, east, and south at the same moment. With Latium faithful
behind her she could not be taken in the rear; the unconquerable
Hannibal did indeed approach her once on that side, but fell away
again like a wave on a rocky shore. From the sea no enemy ever
attempted to reach her till Genseric landed at Ostia in A.D. 455.

Thus it is not difficult to understand how Rome came to be the leading
city of Latium; how she came to work her conquering way into Etruria
to the north, the land of a strange people who at one time threatened
to dominate the whole of Italy; how she advanced up the Tiber valley
and its affluents into the heart of the Apennines, and southward into
the Oscan country of Samnium and the rich plain of Campania. A glance