 The concept religion did not originally refer to a social genus or cultural type. It was adapted from the Latin term religio, a term roughly equivalent to “scrupulousness”. Religio also approximates “conscientiousness”, “devotedness”, or “felt obligation”, since religio was an effect of taboos, promises, curses, or transgressions, even when these were unrelated to the gods. In western antiquity, and likely in many or most cultures, there was a recognition that some people worshipped different gods with commitments that were incompatible with each other and that these people constituted social groups that could be rivals. In that context, one sometimes sees the use of nobis religio to mean “our way of worship”. Nevertheless, religio had a range of senses and so Augustine could consider but reject it as the right abstract term for “how one worships God” because the Latin term (like the Latin terms for “cult” and “service”) was used for the observance of duties in both one’s divine and one’s human relationships (Augustine City of God [1968: Book X, Chapter 1, 251–253]). In the Middle Ages, as Christians developed monastic orders in which one took vows to live under a specific rule, they called such an order religio (and religiones for the plural), though the term continued to be used, as it had been in antiquity, in adjective form to describe those who were devout and in noun form to refer to worship (Biller 1985: 358; Nongbri 2013: ch. 2).