The fact you know about the "rothschilds" should be enough to tell you it's bullshit. The people with the actual power are unseen and unheard. Even this article talks about that, one of these investment companies is completely private.

For one specific example, that does not answer your question, but shows the legal "hidden" power, the Catholic Church has controlled England since 1213. Anything coming from England from that point forward can be considered the actions of the Roman Empire (Catholic Church is the Holy Roman Empire). This only covers one small aspect of the powers, but I wanted to answer your question with something you can see for real.