Linz Castle and Castle Museum.

A deed of gift dating from 799, during the reign of Charlemagne, contains the first mention of the “Castle in Linze” and the church of St Martin. Today, the visitor can see the walls of this castle, together with its bastions and the Friedrich Gate bearing the text A.E.I.O.U. (Alles Erdreich ist Österreichs untertan – All the earth pays tribute to Austria), named after Emperor Friedrich III, who resided here until his death in 1493. As the temporary heart of the Habsburg Empire, Linz was raised by the Emperor to the status of provincial capital. In the 17th century, Rudolf II had the castle built, which today is home to the Upper Austrian provincial Museum.
The south wing was destroyed in the City Fire of 1800, and was rebuilt in modern glass-and-steel architecture for the Capital of Culture year 2009. It now constitute the largest universal museum in Austria. The wings of Linz Castle contain the history of culture collections of the Upper Austrian Provincial Museum.