“The taking of interest was forbidden to clerics from AD 314. It was strictly forbidden for laymen in 1179.
The beginning of the end as far as the total ban on interest was concerned came in the sixteenth century. Although Luther and Zwingli still condemned it utterly, Calvin and some progressive Catholic thinkers such as Collet and Antoine argued that interest-taking did not constitute usury, as long as it represented the real difference between the value of present and future sums of money, and was not mere extortion.
The Catholic Church still forbids usury, meaning extortionate charges, providing penalties in c2354 of the Code of Canon Law, but this does not mean that all interest-taking is sinful.
The Vatican itself invests in interest-bearing schemes, and requires Church administrators to do likewise.
That all interest was not in itself sinful was finally decided in a series of decisions in the institutions of the Catholic Church in the nineteenth century.”
That was cool. I always vaguely knew it was around Luther’s time that Christians first started taking interest as “okay” — and prior to that it was forbidden — but I never knew the exact dates / zones.