Today's Hessian State Parliament building was built in 1840 as a simple city palace in late classical style for Wihelm I., Duke of Nassau.
It was a popular family abode for the Prussian royal and due to a shortage of space, the palace was built right up to the adjacent buildings, and its size turned out to be relatively modest. In 1835, Duke Wilhelm von Nassau engaged the Grand Duchy's Senior Building Director Georg Moller to plan the City Palace but was unable to move in he died in 1839. Instead, his son Adolf became the first and only continuously residing lord of the palace in 1841.
When Duke Adolf was compelled to go into exile in 1866, the Kingdom of Prussia used the palace for the visits of the emperors Wilhelm I and Wilhelm II. In 1925, it became the seat of the British Rhine Army. In 1930 the Prussian State Administration of Palaces installed a museum there.
After serious damage during the Second World War the palace was rebuilt and today it is home to the Hessian House of Parliament.