“Having mis-spent my youth in grad school studying late medieval and early modern European intellectual history, I can now — 20 years after leaving academia — shed some valuable light for you and your readers (as well as for the BBC News).
When Luther said he made his discovery ‘in cloaca‘ (literally translated ‘on the toilet’), he was using one of a long list of late medieval theological-scatological phrases that meant ‘in deepest humility’ or in a state of profound ‘worthlessness’ (i.e., like shit).
So when Luther described arriving at his big theological conclusion ‘in cloaca‘, he (like hundreds of other theologians of the time) was not making a literal reference to his bathroom routine.
If this sounds strange strange today, it shouldn’t. The English language still uses lots of scat lingo (e.g., ‘up shit creek without a paddle’) to express extreme emotions or for emphasis. (‘No shit!’, you might say).
So once again, on major matters of import, the BBC News doesn’t know ‘shit from Shinola’ or its ‘ass from a hole in the ground.'”