Stoicism

Stoicism is a school of Hellenistic philosophy which was founded by Zeno of Citium, in Athens, in the early 3rd century BC. Stoicism is a philosophy of personal ethics informed by its system of logic and its views on the natural world. According to its teachings, as social beings, the path to eudaimonia (happiness, or blessedness) for humans is found in accepting the moment as it presents itself, by not allowing oneself to be controlled by the desire for pleasure or fear of pain, by using one's mind to understand the world and to do one's part in nature's plan, and by working together and treating others fairly and justly. (https://en.wikipedia.org/wiki/Stoicism)
"Stoicism is a tool in the pursuit of self-mastery, perseverance, and wisdom: something one uses to live a great life, rather than some esoteric field of academic inquiry." — (dailystoic.com)
“You become what you give your attention to…If you yourself don’t choose what thoughts and images you expose yourself to, someone else will.” — Epictetus
“You have power over your mind – not outside events. Realise this, and you will find strength.” — Marcus Aurelius