Seitenstetten Abbey was founded in 1112 by Udalschalk, a relative of Bishop Ulrich of Passau, to which he gave all his estates as an endowment. In 1114 the new foundation was settled by monks from Göttweig Abbey. Bishop Ulrich dedicated the church in 1116 and granted the abbey the large parish of Aschbach. In 1142 it also received the large parish of Wolfsbach. Out of these two original parishes were formed the fourteen modern parishes for which the abbey is still responsible.
Despite many setbacks, including two serious fires and many disputes over property, the abbey gradually developed. In 1347 the community had 22 members. After a lengthy period of decline Abbot Benedikt I, formerly prior of the Schottenstift in Vienna, introduced the Melk Reforms at Seitenstetten, thus bringing about a revival in its spiritual and cultural life. This abbot had a chapel built and dedicated in 1440 on the Sonntagberg and so established the Sonntagberger Pilgrimage under the control and protection of the abbey.
Thereafter the abbey was hard hit by the Hungarian disturbances associated with Matthias Corvinus, the Turkish taxes and above all the Reformation; the number of monks declined sharply.
Abbot Christoph Held (1572-1602) started the beginning of spiritual revival with the powerful support of the Imperial Council. Under the abbots that followed, the monastery got its Baroque appearance. After the Thirty Years' War did Abbot Gabriel Sauer (1648-74) finally succeed in stabilising the abbey economically and then in bringing about a true religious renewal.
Abbot Benedikt II Abelzhauser (1687-1717) commissioned Jakob Prandtauer to build the magnificent Pilgrimage Church of the Holy Trinity on the Sonntagberg. The early Gothic abbey church was lavishly refurbished, including work by Franz Joseph Feuchtmayer. Between 1718 and 1747 the Baroque conventual buildings that still stand today were constructed. Ceiling frescoes in the Marble Hall (1735) and the library (1740) were painted by Paul Troger.
After the difficulties of the anti-monastic policies of Emperor Joseph II and of the Napoleonic wars, the abbey gradually regained its strength through the 19th century, until the time of Abbot Theodor Springer (1920-58), who not only brought the abbey safely through the economic crisis after World War I but also through the National Socialist period and World War II without its being dissolved, as so many other monasteries were.
Besides the major works of art and architecture mentioned previously, there are also the Romanesque Knights' Chapel, the picture gallery, and the garden, which contains about 110 different types of rose, mostly historical.References:
From its origin as a small stronghold built by the ancient Illyrian tribe Dalmatae, becoming a royal castle that was the seat of many Croatian kings, to its final development as a large fortress during the Ottoman wars in Europe, Klis Fortress has guarded the frontier, being lost and re-conquered several times. Due to its location on a pass that separates the mountains Mosor and Kozjak, the fortress served as a major source of defense in Dalmatia, especially against the Ottoman advance, and has been a key crossroad between the Mediterranean belt and the Balkan rear.
Since Duke Mislav of the Duchy of Croatia made Klis Fortress the seat of his throne in the middle of the 9th century, the fortress served as the seat of many Croatia"s rulers. The reign of his successor, Duke Trpimir I, the founder of the Croatian royal House of Trpimirović, is significant for spreading Christianity in the Duchy of Croatia. He largely expanded the Klis Fortress, and in Rižinice, in the valley under the fortress, he built a church and the first Benedictine monastery in Croatia. During the reign of the first Croatian king, Tomislav, Klis and Biograd na Moru were his chief residences.
In March 1242 at Klis Fortress, Tatars who were a constituent segment of the Mongol army under the leadership of Kadan suffered a major defeat while in pursuit of the Hungarian army led by King Béla IV. After their defeat by Croatian forces, the Mongols retreated, and Béla IV rewarded many Croatian towns and nobles with 'substantial riches'. During the Late Middle Ages, the fortress was governed by Croatian nobility, amongst whom Paul I Šubić of Bribir was the most significant. During his reign, the House of Šubić controlled most of modern-day Croatia and Bosnia. Excluding the brief possession by the forces of Bosnian King, Tvrtko I, the fortress remained in Hungaro-Croatian hands for the next several hundred years, until the 16th century.
Klis Fortress is probably best known for its defense against the Ottoman invasion of Europe in the early 16th century. Croatian captain Petar Kružić led the defense of the fortress against a Turkish invasion and siege that lasted for more than two and a half decades. During this defense, as Kružić and his soldiers fought without allies against the Turks, the military faction of Uskoks was formed, which later became famous as an elite Croatian militant sect. Ultimately, the defenders were defeated and the fortress was occupied by the Ottomans in 1537. After more than a century under Ottoman rule, in 1669, Klis Fortress was besieged and seized by the Republic of Venice, thus moving the border between Christian and Muslim Europe further east and helping to contribute to the decline of the Ottoman Empire. The Venetians restored and enlarged the fortress, but it was taken by the Austrians after Napoleon extinguished the republic itself in 1797. Today, Klis Fortress contains a museum where visitors to this historic military structure can see an array of arms, armor, and traditional uniforms.