A philosophy or worldview established by Athens-based Cypriot philosopher Zeno (344–262 BCE). (The term ‘Stoic’ can also simply describe a person able to withstand pain with a calm mind, who may have no knowledge of the Stoic worldview.) No complete work survives from Zeno or the two heads of the school who followed him. The major sources for this worldview are Lives of Eminent Philosophers written in Greek by Diogenes Laertius and other works, including Pseudo-Plutarch’s Philosophers’ Opinions on Nature, both written in about the 3rd century CE. Former slave and disabled man Epictetus (c. 50 CE–c.135 CE) contributed two influential Stoic works, Discourses and Enchiridion, transcribed in Greek from his teachings by his pupil Arrian. The Roman emperor Marcus Aurelius (121–180 CE) wrote an important Stoic text as a journal for himself in Latin that is widely known in English as Meditations. Unlike Epicureans, their main but lesser rivals at the time, Stoics believed in the existence of a soul in humans, that it is possible to attain happiness regardless of external circumstances (unconditional happiness) and that the goal of life is to live virtuously and according to the natural world. They placed a high value on rationality. Stoics advocated the essential equality of all humans and rejected notions of superiority based on such things as social rank or nationality. They sought to remind people of the equal humanity of slaves. As with Epicureanism, Stoicism initially flourished in Ancient Greece and Rome before declining when Christianity became the state religion of the Roman Empire in the early 4th century CE, was revived during the European Enlightenment and now has small communities of adherents around the world. Stoicism strongly influenced many worldviews, including Judaism, Christianity and Islam. Stoicism is sometimes called ‘Classical Pantheism’ because of its formative influence on Pantheism. Some figures strongly influenced by Stoicism include French writer François Rabelais, philosophers Voltaire and Diderot, American writer Tom Wolfe, English filmmaker Ridley Scott, British writers James Joyce and VS Naipaul. Stoicism is foundational to the modern psychological treatment, Cognitive Behavioral Therapy. Stoicism offers intelligent ways to navigate adversity and there has been an upswell in online Stoicism discussion groups in the past few years from Western Europe, the Americas, Southeast Asia and Australasia. The Modern Stoicism website modernstoicism.com claims 55,000 members for its Facebook group and identifies visitors from (in numeric order) the US, the UK, Canada, Australia, German, Netherlands, India, Spain, Philippines, Brazil, France, Sweden, Ireland, Italy and Belgium.