Marcus Aurelius was a Stoic philosopher. The Stoics taught that freedom from everyday troubles comes from an interior indifference to external events.
"People seek privacy in holiday places, in small villages on the coast and in the mountains; and you too are wont to desire such things very much. But this is altogether a mark of the most common sort of people, for it is in your power whenever you shall choose to retire into yourself.
For nowhere either with more quiet or more freedom from trouble does a person retire than into his own soul, particularly when he has within him such thoughts that by looking into them he is immediately in perfect tranquility; and I affirm that tranquility is nothing else than the good ordering of the mind.
Constantly then give to yourself this retreat, and renew yourself; and let your principles be brief and fundamental, which, as soon as you shall recur to them, will be sufficient to cleanse the soul completely, and to send you back free from all discontent with the things to which you return.
For with what are you discontented? With the evil people do?
Recall to your mind this conclusion, that rational animals exist for one another, and that to endure is a pare of justice, and that people do wrong involuntarily; and consider how many already, after mutual enmity, suspicion, hatred, and fighting, have been stretched dead, reduced to ashes; and be quiet at last.- But perhaps you are dissatisfied with that which is assigned to you out of the universe?
- Recall to your recollection this alternative; either there is providence or atoms, fortuitous concurrence of things; or remember the arguments by which it has been proved that the world is a kind of political community, and be quiet at last.-
But perhaps corporeal things still trouble you?
- Consider then further that the mind mingles not with the spirit, whether moving gently or violently, when it has once drawn itself apart and discovered its own power, and think also of all that you have heard and assented to about indifference to pain and pleasure, and be quiet at last.-
But perhaps the desire of the thing called fame torments you?
- See how soon everything is forgotten, and look at the chaos of infinite time on each side of the present, and the emptiness of applause, and the changeableness and want of judgement in those who pretend to give praise, and the narrowness of the space within which it is circumscribed, and be quiet at last. For the whole earth is a point, and how small a nook in it is this your dwelling, and how few are there in it, and what kind of people are they who will praise you.This then remains: Remember to retire into this little territory of your own, and above all do not distract or strain yourself, but be free, and look at things as a human being, as a citizen, as a mortal.
Marcus Aurelius (121 - 180 AD) Meditations