He's the company president, but his assistant is 'the (real) power behind the throne'.
In Shakespeare's play, Macbeth kills the king and 'ascends to the throne'.
He 'ascended the throne' [=became king] after the death of his father.
(..) along with your family, were obliged to put their seals to these documents, whereby Lord Wigstan, in the presence of the laity and the clergy of Mercia, accepted both your abdication from the throne and my assumption of it. What? As you see, the devices are legal, the documents, binding. (..)2016 TvShow: Vikings Title: Portage Season: 4 Episode 8