As the citizens of Koblenz strongly strove for independence, Koblenz Castle was aligned as a stronghold against the city. When the Moselle Bridge was built in 1332, the importance of the castle increased and continued well into the 17th century. But with the construction of Philippsburg Castle in Ehrenbreitstein, the Old Castle loses importance, serves as officials' quarters and even becomes a tin factory in 1806. In 1897, the city of Koblenz, by then the owner, modernised the Alte Burg. While since the 1960s the rooms have been used as a library and archive, among other things, the Alte Burg continues to dominate Koblenz's silhouette on the Moselle.