Rerum Novarum was written by Leo XIII. When Robert Prevost took as his papal name Leo XIV, it was a clear signal of priorities, at least to those who are educated in church history and teaching. (There aren’t many names that carry a signal as clear as Leo. The only name that would have been in the same league might have been Francis II).

It should be said that, as in many other fields, it was effectively forced on the church by external development. Marx published The Communist Manifesto in 1848 and Das Kapital in 1867; it took more than a generation for the church to accept that workers' rights were a thing.

Even after that shift, the Catholic Church continued to be a fundamentally reactionary force in the realm of social policies, all the way through the second world war.

Rerum Novarum is an absolute banger. I had the pleasure of discovering it thanks to the discourse surrounding Leo XIV choosing his papal name, and I'm really glad I did. Leo XIII had some really insightful things to say about the problems surrounding workers' rights.