By the 12th century, the lords of Waldsdorf had established their seat on the site of the present stately home in the shape of a fortified manor house with a large dairy farm.
From 1315 to 1605 it was owned by the noble family of Windisch-Graetz.
In 1563 major conversion and renovation work was carried out on the castle under the then-owner and designer, Erasmus of Windisch-Graetz, which saw it expanded into a Renaissance style stately home with a courtyard surrounded on three sides by three-storey high, columnar arcades.
There is still an underground passage, dating to that period, that runs as far as Graz, but it is impassable after the first several hundred metres.

From 1605 to 1622 the house was owned by Bernard Walter of Walthersweil and, from 1622 to 1624, by the Schranz of Schranzenegg family, who sold it to Siegmund Friedrich, Count Trautmannsdorff.
During the rule of Sigmund Frederick the Younger of Trautmannsdorff, Oberthal House was converted and expanded between 1656 and 1661 into one of the most splendid in the area around the state capital.
Above the house, a large pleasure garden (Lustgarten) was established, based on French prototypes, surrounded by a wall and decorated with grottos and a small maison de plaisance.
In 1798 Thal House and its estate was sold to Leopold Edler of Warnhauser and remained in the possession of his family until 1841.
From 1841 onwards the palace was owned by the Freiherren of Walterskirchen.
In 1846 the house was remodelled into the Romanesque style of a Scottish castle.

In 1905 Oberthal was sold to a Slovenian consortium, who had to give up the property after a short time for financial reasons.
The house subsequently changed hands several times in the ensuing period and steadily fell into a state of dilapidation until it ended up in the hands of Dr. Friedrich Schuster, who had the building repaired again, getting rid of the 1846 modifications and reinstating its original Baroque appearance.
In 1940 the house and the estate went to the Essberger family.
From 1945 to 1955 the British garrison headquarters was located here, and from 1955 to 1957 part of the house was rented to the British ambassador.
On 1 November 1958 the house was restored to John Theodor Essberger, who died in 1959, whereupon his daughter, Lieselotte von Rantzau inherited it.
Frau Liselotte von Rantzau died in 1993, since when it has been owned by her sons, Dr. Eberhart and Heinrich von Rantzau.
By the 12th century, the lords of Waldsdorf had established their seat on the site of the present stately home in the shape of a fortified manor house with a large dairy farm. From 1315 to 1605 it was owned by the noble family of Windisch-Graetz. In 1563 major conversion and renovation work was carried out on the castle under the then-owner and designer, Erasmus of Windisch-Graetz, which saw it expanded into a Renaissance style stately home with a courtyard surrounded on three sides by three-storey high, columnar arcades. There is still an underground passage, dating to that period, that runs as far as Graz, but it is impassable after the first several hundred metres.
From 1605 to 1622 the house was owned by Bernard Walter of Walthersweil and, from 1622 to 1624, by the Schranz of Schranzenegg family, who sold it to Siegmund Friedrich, Count Trautmannsdorff. During the rule of Sigmund Frederick the Younger of Trautmannsdorff, Oberthal House was converted and expanded between 1656 and 1661 into one of the most splendid in the area around the state capital. Above the house, a large pleasure garden (Lustgarten) was established, based on French prototypes, surrounded by a wall and decorated with grottos and a small maison de plaisance. In 1798 Thal House and its estate was sold to Leopold Edler of Warnhauser and remained in the possession of his family until 1841. From 1841 onwards the palace was owned by the Freiherren of Walterskirchen. In 1846 the house was remodelled into the Romanesque style of a Scottish castle.
In 1905 Oberthal was sold to a Slovenian consortium, who had to give up the property after a short time for financial reasons. The house subsequently changed hands several times in the ensuing period and steadily fell into a state of dilapidation until it ended up in the hands of Dr. Friedrich Schuster, who had the building repaired again, getting rid of the 1846 modifications and reinstating its original Baroque appearance. In 1940 the house and the estate went to the Essberger family. From 1945 to 1955 the British garrison headquarters was located here, and from 1955 to 1957 part of the house was rented to the British ambassador. On 1 November 1958 the house was restored to John Theodor Essberger, who died in 1959, whereupon his daughter, Lieselotte von Rantzau inherited it. Frau Liselotte von Rantzau died in 1993, since when it has been owned by her sons, Dr. Eberhart and Heinrich von Rantzau.
Thal, Styria