tus_, in fierce opposition to Caesar, and on the side
of the Senate. If this is so, the poem was probably written between
B.C. 60 and 55. The lines on ambition and its attendant evils (as iii.
931 _sqq._, v. 1117-35, etc.) may have been written with a special
view to the facts of Memmius' life. Lucretius may refer to his
recollection of the civil wars in v. 999,

'At non multa virum sub signis milia ducta
una dies dabat exitio.'

In ii. 40 _sqq._ there is perhaps a reference to Caesar's army in the
Campus Martius at the beginning of B.C. 58.

The _de rerum natura_ is an exposition of Epicureanism, especially on
its physical side; i. 54,

'Nam tibi de summa caeli ratione deumque
disserere incipiam et rerum primordia pandam,' etc.

The title is taken from Epicurus' +peri physeos+, which Lucretius
followed closely, as is evident from the account of the Epicurean
philosophy in Diogenes Laertius, x., and from the fragments of
Epicurean writers discovered at Herculaneum in 1752. He probably used
as his model Empedocles' poem +peri physeos+.

The object of the poem is to deliver men from the fear of death and of
the gods; iii. 37,

'Et metus ille foras praeceps Acheruntis agendus';

i. 62-101; cf. l. 101,

'Tantum religio potuit suadere malorum.'

Note that the invocation to Venus at the beginning of the poem is not
inconsistent, but is an address to the universal principle of
generation; cf. i. 21,

'Quae quoniam rerum naturam sola gubernas.'

The scope of the Books is as follows: Books i. and ii. state the
physical theories of Democritus and Epicurus. Book i. states the
Atomic Theory of Democritus, held by Epicurus, that the world consists
of atoms and void. The theories of Heraclitus, Empedocles, Anaxagoras,
etc. are refuted; i. 740,

'Principiis tamen in rerum fecere ruinas
et graviter magni magno cecidere ibi casu.'

Book ii. treats of the combinations of atoms, and the principle of the
swerve introduced to explain free-will. The varieties of atoms are
shown to be limited. In Book iii. the nature of the mind and life is
shown to be material. _Religio_ and the fear of death (cf. ll. 978
_sqq._) are attacked principally in this Book; iii. 830,

'Nil igitur mors est ad nos neque pertinet hilum,
quandoquidem natura animi mortalis habetur.'

Book iv. treats of the theory of _simulacra_ or images, of the senses,
and particularly of love. Book v. treats of the formation of the earth
a