From outside the State Hall takes up the whole front of Josef’s Square. It has a length of 77.7 m., a width of 14.2 m., and a height of 19.6 m. Two side wings and a cupola space give the interior a three-part structure. The cupola has an oval horizontal shape with the measurements 18 m. and 29.2 m., and a height of 29.2 m. The wings are divided by two massive pair of columns, the “pillars of Hercules”, that present Charles VI’s motto “Constantia et fortitudine” (by persistence and courage) as well as his pretensions to power in Spain.
Not long after the death of Emperor Charles VI in 1740 cracks appeared in the cupola of the Hall. The building threatened to cave in. The court architect Nicolaus Pacassi projected a new plan to save the library, and it was carried out in 1767. An iron ring was inserted into the cupola oval. In the passage between the cupola and the side wings two supporting pillars were set up.