During the
Investiture Controversy in the early twelfth century,
Margrave Leopold III of
Babenberg sided with the Papacy against
Emperor Henry IV. In 1106, the emperor's son,
Emperor Henry V, who sided with the Papacy against his father, rewarded Leopold's loyalty by offering him his sister
Agnes' hand in marriage, in recognition of his services. Agnes was the widow of
Duke Frederick I of Swabia. Leopold, who was recently widowed from his first wife, accepted the hand of this daughter of the Imperial
Salian dynasty. With this new connection to two imperial families, Leopold's status was elevated by the marriage, which also brought with it a large dowry of royal possessions. Following his marriage, Leopold initiated plans to build a castle on
Leopoldsberg for his new residence, which had formerly been at
Gars am Kamp and
Tulln an der Donau. He named the new castle
Niwenburc. In 1113, Leopold founded a monastery (
kloster) for secular
canons next to his castle, providing it with generous donations of land. The cornerstone ceremony for the new abbey church took place on 12 June 1114. The form of that original basilica has survived for nine centuries, despite many subsequent modifications and reconstructions. Most likely the two side aisles had lofts, the middle aisle was most likely higher, and above the crossing there was a tower. On 13 September 1330, the town and monastery were seriously damaged in a fire. The monastery and abbey church were renovated, and new works of art were commissioned by provost Stephan of Sierndorf. In 1394, construction began on the south tower of the early-Gothic abbey church. It would take two centuries before the tower was completed in 1592. In 1636, the crossing tower was demolished. In the fall of 1683, a massive Ottoman army under the leadership of
Kara Mustafa Pasha laid
siege to Vienna and threatened Klosterneuburg. Most of the town and monastery escaped with the members of the imperial court, but two men—one priest and one lay brother—remained behind with the citizens to defend the town and monastery. The lower part of the town was surrendered to the attackers, but the upper part and the monastery were defended successfully. The final phase of remodeling the abbey church in the Baroque style took place between 1723 and 1730. During this period, the presbytery, choir stalls, high altar, court oratorio, and pews were all remodeled. In 1836, construction of the monastery resumed, and by 1842, the residential wing, the south wing, and the west wing were finished by
Neoclassical architect
Joseph Kornhäusel from Vienna. Only two of the planned nine domes were completed. The main dome bears the imperial crown, and the smaller dome the archducal crown. In 1879, a major restoration project was initiated, according to plans by
Friedrich von Schmidt. During this period, the vestry and choir chapel were erected, as well as the
neo-Gothic twin steeples. Between 1898 and 1901, the mural paintings in the side chapels were created by Karl Peyfuss. In 1911, the course of the
Danube was regulated to its current location, about two kilometers from the monastery. In 1936, the abbey church was granted the title
Basilica minor by
Pope Pius XI. Among the most notable of priests of the abbey was Father
Pius Parsch, who promoted the "volksliturgischen" or "People's Mass". This early practice of the liturgical renewal was notable for celebration at a free standing altar with the priest facing the people, gothic vestments and an emphasis on the liturgical seasons rather than the calendar of the saints. These features were all permitted but uncommon prior to Vatican Council II. The
Anschluss of 1938 brought devastation to the Klosterneuburg community. In 1941, the Nazis suppressed the canonry and confiscated the buildings and properties. Only a few canons were permitted to remain and continue ministering to the faithful. Some canons went out into the parishes, others were drafted into the army, and many lost their lives because of their involvement in the resistance movement. Immediately after the war, some canons were murdered for standing up against the Russian soldiers who preyed on Austrian women and girls. Provost Alipius Linda, elected in 1937, guided the community wisely through both the Nazi period and the subsequent Communist occupation. During the post-war period, Provost Gebhard Koberger presided over the rebuilding of the abbey's financial condition, as well as the reconstruction of several of the monastery's churches which had been damaged or destroyed by the bombing. Provost Gebhard was elected Abbot General of the Austrian Congregation and attended the
Second Vatican Council. In 1969, he was elected Abbot Primate of the Confederation of Augustinian Canons. In 1985, on the celebration of his golden jubilee of priesthood, Provost Gebhard inaugurated the Provost Gebhard Koberger Institute for Research on the Augustinian Canons. He resigned due to poor health in 1995, and died in 1997. ==Verdun Altar==