Lucretius, De Rerum Natura
William Ellery Leonard, Ed.

     Afterwards,
When huts they had procured and pelts and fire,
And when the woman, joined unto the man,
Withdrew with him into one dwelling place,
     . . . . . .
Were known; and when they saw an offspring born
From out themselves, then first the human race
Began to soften. For 'twas now that fire
Rendered their shivering frames less staunch to bear,
Under the canopy of the sky, the cold;
And Love reduced their shaggy hardiness;
And children, with the prattle and the kiss,
Soon broke the parents' haughty temper down.
Then, too, did neighbours 'gin to league as friends,
Eager to wrong no more or suffer wrong,
And urged for children and the womankind
Mercy, of fathers, whilst with cries and gestures
They stammered hints how meet it was that all
Should have compassion on the weak. And still,
Though concord not in every wise could then
Begotten be, a good, a goodly part
Kept faith inviolate- or else mankind
Long since had been unutterably cut off,
And propagation never could have brought
The species down the ages.