One of the most prominent structures in the city is Bratislava Castle, situated on a plateau  above the Danube. The castle hill site has been inhabited since the transitional period between the Stone and Bronze ages and has been the acropolis of a Celtic town, part of the Roman limes Romanus, a huge Slavic fortified settlement, and a political, military and religious centre for Great Moravia. A stone castle was not constructed until the 10th century, when the area was part of the Kingdom of Hungary, however, also in 9th century a pre-romanesque stone basilica, was standing in the area of the hillfort.