The ruin is located at 632 m above sea level. M. on the Säli, a secondary summit of the Engelberg chain, which overlooks the Aare valley and the Wiggertal. The Neu-Wartburg (also called Sälischlössli) is only 150 meters further north, but in the area of the Starrkirch-Wil community.
Shortly before the year 1200, the lords of Ifenthal had the castle built. Older research was carried out by the Counts of Frohburg. From 1201 a Werner von Ifenthal can be found in documents; with the construction of the Alt-Wartburg and later the Neu-Wartburg, the Ifenthalers probably tried to break away from their vassal relationship with the Frohburgers. A significant expansion took place during the 13th century and structural development was completed in 1325.
In the middle of the 14th century, the Alt-Wartburg came into the possession of the related lords of Büttikon. They sold the property to Hallwyler in 1379. When the Confederates conquered Aargau in 1415, Bernese troops burned down the two Wartburgs. While the Hallwylers later rebuilt the Neu-Wartburg, they let the Old-Wartburg fall to ruin. In 1966/67 the remains of the wall were excavated and restored. Smashed remains of tiled stoves and clay tiles from a fallen floor were discovered in the layer of fire.
Source: Wikipedia