I want to know the answer to the following question:
In which centuries did a proliferation of secret treaties occur that led the United Nations Charter to include an obligation to register treaties to be invoked before it?
All the background I'm provided with is that "The United Nations Charter states that treaties must be registered with the UN to be invoked before it or enforced in its judiciary organ, the International Court of Justice.". Is that enough to answer the question?
Answer: no