The area around Wartau was first settled around 9000 years ago, culminating in neolithic settlements on the nearby Ochsenberg and Prochna Burg at about 3000 BC. A Merovingian fortress was built at Prochna Burg, but was destroyed around 750. While there are no written records that mention the first owner of the castle or when it was built, the wooden beams in the castle have been dated to about 1225. It was probably built as an administrative center for royal estates in the area. It may have been built by the Graubünden Freiherr von Sagogn, because around 1320 it was inherited by Count Hugo III von Werdenberg-Heiligenberg from the Freiherr von Wildenberg who was related to the Freiherr vonf Sagogn.
The castle first appears in the historical record in 1342 when Johannes von Belmont pledged it to his wife Adelheid von Klingen in exchange for 250 silver marks. In the following decades the Belmont family fought the Werdenberg-Heiligenbergs until the death of Ulrich Walter von Belmont in 1371 and the extinction of the Belmont family. The castle probably returned to the Werdenberg-Heiligenberg family and was occupied by their vassals for the next couple decades. Around 1390 the castle was owned by the related Werdenberg-Sargans. In 1393 as the two families fought for territory, the castle was besieged for eleven days. In 1399 it returned to the Counts of Werdenberg-Heiligenberg.
During the 14th century the castle was expanded several times, but by the 15th century it began to be neglected. In 1414 Count Rudolf II sold Wartau to his cousin Count Friedrich VII of Toggenburg, but six days later converted the sale into collateral for a loan. The Counts of Werdenberg-Heiligenberg died out in 1428, before they could redeem the loan. Eight years later Friedrich VII died, ending the Toggenburg line and starting the Old Zürich War over the Toggenburg inheritance. After the war it was inherited by the Freiherr von Thierstein, but after their extinction it passed through the von Limburg, Montfort-Tettnang and Sax-Misox families before it was sold in 1485 to the city of Lucerne. However, Wartau was too far from Lucerne and in 1493 they sold it to the Barons of Kastelwart. The Barons were faithful supporters of the Habsburgs, which caused conflicts with the villagers who supported the Swiss Confederation. In 1498 they sold the castle and lands to the Swabian von Hewen family. In the following year Matthias von Kastelwart died in the Battle of Dornachagainst the Swiss. In 1517 the Hewen family sold the castle and lands to the Canton of Glarus. However, the Glarus appointed Landvogt lived at Werdenberg Castle and so the castle at Wartau lost its administrative role and was abandoned around 1530.
Following the collapse of the Helvetic Republic and the creation of the Canton of St. Gallen in 1803, Wartau became part of the new Canton. The castle ruins were sold in 1818 to a private owner. It was donated to the municipality in 1911 and restored in 1932. In 1982 it was again repaired and restored, followed by a survey and excavations in 2002.
The castle consists of either two square towers built next to each other or a single rectangular tower which was divided into two. The north-eastern tower was about four stories tall, while the south-western tower was lower and divided into apartments. Around 1300 a crenellated parapet was added around the top of both towers. In the 14th century an additional story was added to the top of both towers along with new parapets and a flat roof. The new upper story is still visible as it was built from different stone. Around 1500 the upper story was rebuilt. The castle is surrounded on three sides by a ring wall, which ran along a steep cliff.References:
Hochosterwitz Castle is considered to be one of Austria's most impressive medieval castles. The rock castle is one of the state's landmarks and a major tourist attraction.
The site was first mentioned in an 860 deed issued by King Louis the German of East Francia, donating several of his properties in the former Principality of Carantania to the Archdiocese of Salzburg. In the 11th century Archbishop Gebhard of Salzburg ceded the castle to the Dukes of Carinthia from the noble House of Sponheim in return for their support during the Investiture Controversy. The Sponheim dukes bestowed the fiefdom upon the family of Osterwitz, who held the hereditary office of the cup-bearer in 1209.
In the 15th century, the last Carinthian cup-bearer, Georg of Osterwitz was captured in a Turkish invasion and died in 1476 in prison without leaving descendants. So after four centuries, on 30 May 1478, the possession of the castle reverted to Emperor Frederick III of Habsburg.
Over the next 30 years, the castle was badly damaged by numerous Turkish campaigns. On 5 October 1509, Emperor Maximilian I handed the castle as a pledge to Matthäus Lang von Wellenburg, then Bishop of Gurk. Bishop Lang undertook a substantial renovation project for the damaged castle.
About 1541, German king Ferdinand I of Habsburg bestowed Hochosterwitz upon the Carinthian governor Christof Khevenhüller. In 1571, Baron George Khevenhüller acquired the citadel by purchase. He fortified to deal with the threat of Turkish invasions of the region, building an armory and 14 gates between 1570 and 1586. Such massive fortification is considered unique in citadel construction.
Since the 16th century, no major changes have been made to Hochosterwitz. It has also remained in the possession of the Khevenhüller family as requested by the original builder, George Khevenhüller. A marble plaque dating from 1576 in the castle yard documents this request.
A specific feature is the access way to the castle passing through a total of 14 gates, which are particularly prominent owing to the castle's situation in the landscape. Tourists are allowed to walk the 620-metre long pathway through the gates up to the castle; each gate has a diagram of the defense mechanism used to seal that particular gate. The castle rooms hold a collection of prehistoric artifacts, paintings, weapons, and armor, including one set of armor 2.4 metres tall, once worn by Burghauptmann Schenk.