If you want to read the actual report rather than some twitter thing... And yea these are multi-stage rockets, but of the small sort common in warfare back then. It really is a misnomer to compare it to modern multistage rockets. Still cool though. Rockets and various sort of launched grenades have been used for thousands of years in warfare.
That said, there is a drawing of a house upon a rocket. But you do find weird versions of things like this appearing in history, eg water wheels or houses in the sky.
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