Mattsee is a market town at the eponymous lake in the district of Salzburg-Umgebung in the Austrian state of Salzburg.

765, Duke Tassilo III of Bavaria established the Mattsee Benedictine Abbey, which became a part of the Diocese of Passau in 993 and was transformed into a college of canons.

The abbey church, a Gothic building, has a Baroque equipment and a prominent 60m/197 ft high steeple added in 1766.

Adjacent is a museum showing paintings of Johann Michael Rottmayr, an astronomical clock, and an 860 grant deed by King Louis the German.

[3][4] The fahr(T)raum museum exhibits the car collection of Ernst Piëch, grandson of Ferdinand Porsche.