Another common name for a toilet like this is a "Thunderbox". Some country houses in England were still using them into the fifties and sixties. A few had quite sophisticated one off flushing mechanisms with brass fittings.
How odd. My grandmother would call it a "throne". I never heard anyone else call it that until now. (She would only say that when referring to my grandfather, "he's on the throne" perhaps she had some resentment over him as "King" of the house and showed it in that way.) a rude story maybe, but your title brings back the memory O_o