Tagstein Castle, Medieval castle in Masein, Switzerland

Tagstein Castle is a medieval fortress ruin perched on a hillside near Masein in the Grisons region. The remaining stone walls display defensive construction techniques typical of the era, with visible foundations and structural elements.

The oldest part of the castle dates from the early 13th century, with a predecessor building documented in 1160. In 1342 Kunigunde von Vaz and her husband Count Friedrich VII of Toggenburg enfeoffed the castle to the brothers Hug, Sigfrid and Johann Thumb. In 1385 Anna Schauenstein sold the stronghold to the Barons of Rhäzüns, and around 1700 the Capol family of Flims acquired the estate.

The ruins display regional building methods that shaped this area for centuries. Visitors notice in the stonework patterns and layout how local craftspeople worked with available materials and terrain.

The castle is a private property with adjoining farm buildings and is not open to the public, so it can only be viewed from outside. It stands on a spur northwest of Thusis near Masein; the related ruin of Obertagstein lies above Thusis. The property was put up for sale in May 2024.

The fire that reshaped the castle came in 1899, not the 15th century: the owners, the von Planta family, rebuilt it in a historicist style. The present form, with its hipped-gable roof and raised tower section, and most of the interior date from this reconstruction. A Capol-Schorsch coat of arms stone sits above the entrance gate on the west front.