After death the sensation is either pleasant or there is none at all. But this should be thought on from our youth up, so that we may be indifferent to death, and without this thought no one can be in a tranquil state of mind. For it is certain that we must die, and, for aught we know, this very day. Therefore, since death threatens every hour, how can he who fears it have any steadfastness of soul?

Cato Maior de Senectute – On Old Age (44 BC), section 74