Kanon is Greek for a straight rod, the carpenter's rule; the root means reed, the same root as the English cane. The First Council of Nicaea in 325 called the church's disciplinary measures canons. Around 1140 the Bolognese teacher Gratian compiled the Concordia discordantium canonum, known as the Decretum, nearly 3,800 texts reconciled into one method, and canon law became a taught profession. Church sources and legal historians describe the result as the first modern Western legal system and the oldest continuously functioning one: codified in 1917, revised in 1983, in force today.
Legal historians trace the corporate person, an entity that can own property, sue, be sued, and outlive every member, to medieval canonists: Pope Innocent IV, himself a canon lawyer, is credited with articulating the persona ficta in the thirteenth century, giving religious houses a legal body no bishop could die out of. Harold Berman's Law and Revolution argues the papal legal revolution of the twelfth century invented the Western legal tradition outright.
The same code criminalized interest: the Second Lateran Council in 1139 condemned usurers, and Gratian's Decretum carries the ban in Causa 14. Yet an institution that forbade interest still needed credit, and the exceptions, contracts, and workarounds canon lawyers built around their own ban became part of the machinery commerce runs on. The reading that follows: the church did not just coexist with early capitalism, it drafted its legal skeleton while preaching against its blood.
A system that criminalized lending at interest also perfected the corporation. Which of those two inventions do you live under today?