[1] The castle ruins are situated at about 300 metres (980 ft) above the right bank of the Danube on an outcrop running from east to west.

It was besieged and conquered in 1230/31 during the uprising led by Hadmar III and his vassals against Duke Frederick II of Austria.

Thus Leutold Kuenring outmanoeuvred the Austrian nobility in their revolt against Duke Albert: subsequently, the castle was besieged and conquered in turn in 1295/96.

Hence his nickname, "Schreckenwald", (wordplay on his family name, Scheck von Wald, meaning "Terror Forest"), which is said to have been given to him because of his cruelty towards the population.

[2] In 1477, Duke Leopold III acquired the castle and occupied it with tenants and caretakers in order to stop the raids.

[2] Today, the Aggstein ruins receive about 55,000 visitors annually, making it one of the most popular tourist attractions in Lower Austria.

Only parts of the foundation on the so-called Bürgel (small castle) on the western outcropping, and on Stein, a rock structure on the east side, originate from this time.

After her death there was no-one to stop its decline, and stones and timber were taken and used to erect a Servite Order convent on nearby Maria Langegg [de].

The project was able to repair defective masonry; put sewers, water supply and utilities back into working order; reshape the entrance area and create a new banquet hall.

Hadmar III von Kuenring is alleged to have captured ships travelling downriver with an iron chain stretched across the Danube.

The Duke granted Hadmar his life and liberty on the condition that he returned all the stolen goods and atoned for the injuries he had inflicted.

Another legend tells how the cruel Jörg Scheck vom Walde confined his most troublesome prisoners on a tiny outdoor platform.

One of his victims is said to have survived the leap into the treetops below, alerted Duke Albert to the crimes being committed and guided his troops into the castle by a secret route.