Built probably in the early 13th century AD by the
House of Rapperswil, the castle secured the strategically important river crossing in the area between the
Grafschaft Rapperswil and the
House of Toggenburg. The property was documented in 1311, when the castle was taken by force by Rudolf von Laufenburg-Rapperswil probably from the
Toggenburg family. It's again mentioned on the occasion of the battle of Grynau on 21 September 1337, when
Count Johann I was killed: Graf
Diethelm von Toggenburg moved with a fleet, numerous soldiers and siege material from Zürich over the
Obersee to the Grynau Castle, which at that time was still located at the confluence of the Linth river in the former
Tuggenerse. The castle was a base of the "outer Zürich" (
äusseres Zürich) alliance of 1336 in the feud of the House of Rapperswil against the city of Zürich. Although they thereby passed the city of
Rapperswil, the Zürich troops were convinced not to be bothered, due to their large number. Hidden by the lake shore
Buchberg, Graf Johann landed soldiers, and from the wooded eastern slope of the mountain, they raided the Zürich troops carelessly encamped at the Grinau Castle, who, leaderless, fled to their ships, and Graf Diethelm was taken as a prisoner. As the Zürich troops noted that Graf Johann had just a handful of soldiers, they competed for the counterattack, and killed Johann von Habsburg-Rapperswil; Diethelm was killed by Johann's abiders. Thereafter, the castle was sold by the sons of Count Johann I (among them
Johann II von Rapperswil) around 1343/47 to
Friedrich V von Toggenburg, but after the extinction of the House of Rapperswil, in 1436/37 the property including all rights – especially the bridge toll – passed to the
Old Swiss Confederacy; it was claimed by the canton of Schwyz, to control all traffic between the Eastern and Central Switzerland, as well as between the city republic of Zürich and the
Gotthard Pass. Gräfin
Elssbeth von Toggenburg, née
von Maetsch, was mentioned as sole heir in two documents of the city council of Zürich, and she certified on 31 October 1436,
in view of the diverse services by Zürich for Fridrich, and given the fact that a widow requires special protection, with help of her uncle and legal counsel, Fridrich of Hewen, the she gave over to the city of Zürich as property the towns
Utznang,
Schmerikon and
Utznangerberg (a castle on the Uznach mountain) with all its rights. The transfer is valid "zuo stund" (now), and the inhabitants of the territories have to swear to the people of Zürich until next
Hilariustag (13 January 1437); the Countess maintained all servitudes by lifetime. The privileges and the tradition of the (Toggenburg) residents will be respected, notably with regard to the so-called
third penny in inheritances and the so-called
Kirchsatz; Zürich will also not impose any taxes. The commitment, Count Fridrich has concluded with Schwyz, related to the
tower at Grinow will by complyed by Elisabeth. On 16 February 1437
Elisabeth von Matsch granted the mayor and council of the city of Zürich or their representatives the authority to act on their behalf, immediately after the usurpations of lands of the Toggenburg County by the cantons of Schwyz and Glarus, and to lock
Grynow. In the summer of 1799, the French and Austrian troops fought in the Second Coalition War at the strategically important bridge which was destroyed three times, and rebuilt, and occupied by the French troops in the aftermath of the
Second Battle of Zurich. Again in 1833, Swiss federal troops were concentrated at the Grynau castle, on occasion of the then planned division of the canton of Schwyz, however, waived without an armed intervention. And again in a Swiss civil war, the so-called
Sonderbundskrieg, federal troops crossed the important bridge in March 1847, without a single dead soldier on both sides. In 1849 respectively 1879 the remaining buildings, the tower, the adjacent barn and the former accommodation building, were bought for then 35,000 Swiss Francs by
Schlossvogt Kälin, who rebuilt the surrounding building into the
Landgasthof Schloss Grynau, a country inn, which is still held by the family. == Architecture ==