According to the abbey chronicle, Øm Abbey was founded in 1172 by Cistercian monks from Vitskøl Abbey in northern Jutland. They wanted to found a daughter house in central Jutland. They attempted to establish such a house at Sabro near Århus but found the soil useless for farming. They moved to Sminge near Silkeborg and found the same poor soil conditions, and then in 1166 they settled a short time at abandoned Veng Abbey, outside Skanderborg. They left in 1167 because of unresolved land disputes with Lady Margrethe. They tried for four years to establish themselves at Kalvø in Lake Skanderborg, but the winters proved to be too harsh. The monks finally settled on a patch of land near the town of Rye between Moss Lake and Guden Lake surrounded by water and marsh. The site was overgrown with brush and surrounded by forest.
The abbey was dedicated to the Virgin Mary and was called 'Cara Insula' or the "dear Island".
The Øm Abbey Chronicle was written by local monks from 1206 to 1267 when it abruptly ends. It outlines events at the abbey during the tumultuous years of the early 1200s.
Bishop Svend of Århus trasferred many of his own holdings to Øm Abbey and then retired there to live out his days among the monks. He was buried in front of the high altar. Abbot Michael, the twelfth abbot, was buried in the chapter room in the unfinished church. Bishop Peder Elafssen of Århus was buried in the church in 1246, years before it was completed. Abbot Jens (1246-1249) was wounded while trying to prevent bandits from stealing horses from the abbey.
The second abbey church was completed in 1257 built of red bricks, the most common building material of the day in the region. It was built in late Gothic style, with a nave nad a transept, but had an irregular shape.
One event which caused trouble for Øm Abbey was the suspicion that the monks harbored Abbot Arnfast of Ryd Abbey who was accused of having murdered King Christopher I of Denmark by giving him poisoned communion wine during mass at Ribe Cathedral in 1259. Abbot Arnfast was supposed to have poisoned the king for his persecution of Archbishop Jacob Erlendsen. A thorough search failed to produce Arnfast, who had fled the country, but any regard that Christopher's son, King Eric V, had had for the Cistercians vanished.
In 1260 the Dowager Queen Margaret Sambiria, who was Christopher's widow and the mother of King Eric, stayed at the abbey for two days with an army of 1,600 knights. The chronicle bemoans on the heavy cost of such a royal visit.
The next two Bishops of Århus were not kindly disposed to Øm Abbey. They reclaimed some of the properties given by earlier bishops. They also claimed the right of hospitality at the abbey for themselves and their followers, which angered the monks. The Cistercians continued to support Archbishop Jacob Erlandsen in his struggle with King Valdemar. The chronicle ends abruptly in 1267 and was not added to by subsequent writers.
At its height in the late 1400s, the abbey consisted of the church, hospital and hospital cemetery, library, chapter house, refectory, dormitory, cloister and cloister garden, and a guest house. The abbey measured approximately 120 meters by 80 meters. It was one of Denmark's richest houses with land holdings, mills, and a well-recognized hospital. Cistercians were excellent farmers and over time the abbey came into possession of many properties which brought additional income and prestige.
One of the important improvement the monks made to the site was to build three canals. Brother Martin discovered that Moss Lake was about a cubit higher than Lake Guden. The monks used that difference to build two canals near the abbey, one to bring fresh water to the abbey and a second to serve as a primitive sewerage system. The third canal built farther away from the abbey connected the two lakes and was used to transport goods through the lake region.
The abbey prospered especially during and after the reign of Queen Margaret I of Denmark. By 1510 the abbey owned 250 properties all over central Jutland.
The Reformation in Denmark brought about the end of the abbey. When Denmark became officially Lutheran in 1536, the abbey was allowed to continue operating with the monks already there, but no new monks were to be admitted. In 1560 the last monk was moved to Sorø Abbey on Zealand, and the land and buildings became crown property under Frederik II. Just a year later, in 1561, Frederik II ordered the buildings to be demolished, and the stone, timber, and bricks used to extend Skanderborg Castle. The land on which the abbey had been located was divided into four large estates in 1571.
The town of Emborg grew on the site of the abbey and now surrounds the it, which has become part of the National Historic Museum system of Denmark.
- Øm Kloster Årbog