Compare and contrast existentialism and stoicism?

Ithink you just slapped me with a dictionary

Stoicism was a school of philosophy that was popular in hellenistic greece and was popularised (so tofollowers of stoicism understood that one individual cannot change the course of life and the universe. that the world is full of chaos and misery and horrific events and just plain bad luck. that you  must always be mentally prepared to face all of these things, rather than build yourself up higher and higher with hope and false optimism only tofall far further down when you face    speak) by seneca,epictetus and marcus aurelius.