For ancient Romans, 'religio' could describe an elephant gazing at the sky
The world has roughly 10,000 distinct religions, yet four of them plus the nonreligious cover 97.6 percent of humanity. Stranger still, the word itself once had little to do with gods: Romans used religio for caution, duty or dread, and the idea of religion as a separate sphere of life only took shape in the 1500s.
Scholars cannot agree on what counts as a religion; the term is often called essentially contested. Broadly, it covers social and cultural systems of practice, ethics, texts, sacred places and organisations that link people to the supernatural or transcendent. Why humans became religious at all is still open, with suggestions ranging from awareness of death to the pull of community and the experience of dreams.
The numbers are lopsided. Christianity, Islam, Hinduism and Buddhism together account for more than 73 percent of people, and every other faith combined makes up about 2.4 percent. Some researchers think global religiosity may rise simply because more religious countries tend to have more children. The unaffiliated include atheists and agnostics, though many in that group still hold spiritual beliefs of some kind.
The etymology is itself an argument. Cicero traced religio to relegere, to go over again or weigh carefully. Lactantius and later Augustine preferred religare, to bind fast, a reading popularised in modern times by writers such as Joseph Campbell. In practice Romans used the word loosely. Julius Caesar applied it to the binding force of a captive soldier's oath, and Pliny the Elder to the apparent reverence elephants showed the night sky. It could mean scruple, hesitancy or anxiety, and was sometimes set beside superstitio, meaning excessive fear.
When the word reached English around the 1200s, it meant a life under monastic vows. Only in the 1500s did Europeans begin separating religious matters from worldly ones, using the term to divide church authority from civil rule. The Peace of Augsburg is one such case, which the scholar Christian Reus-Smit has called the first step toward a European system of sovereign states.
Source: Religion
