The area was settled since
ancient times, when a
Roman road led through the Lavanttal up to the
Obdach Saddle pass and the
Mur valley in present-day
Upper Styria. In the 11th century, the surrounding
Carinthian estates were enfeoffed to the
Bishops of Bamberg by Emperor
Henry II. A first chapel dedicated to
Saint Leonard was consecrated during the tenure of Bishop
Otto (1102–1139). His successors also had
Gomarn Castle erected in order to protect their possessions, mainly from the rivalling
Bishops of Lavant who resided at nearby
Twimberg Castle. The settlement below the chapel was first mentioned in a 1278 deed, its citizens already had received
town privileges by 1311, at the time when the
Gothic parish church was erected. In the 15th century, mining for gold and silver became common in the area, run by the
Fugger merchant family from
Augsburg. Also, Sankt Leonhard became known for its
mineral springs (
Preblauer); the waters were mentioned by the physician
Paracelsus in 1538. The Bamberg bishops finally sold the estates to the
Habsburg empress
Maria Theresa in 1759. Sankt Leonhard received the official status of a spa town (
Bad) in 1935. During the
Great Depression in the 1930s, several medieval
stained glass windows of the parish church were sold and are now on display at
The Cloisters museum in
New York City. ==Politics==