From Wikipedia - Aarhus Cathedral (Danish: Århus Domkirke) is the main religious edifice of Aarhus, Denmark, in the Jutland peninsula in the western part of the country. The cathedral is dedicated to the patron saint of sailors, St. Clemens, and located at the address Domkirkepladsen 2, 8000 Århus C, Denmark, on the port-side of the central market of the town, Store Torv (lit. Danish: Large Square). The church is the longest in Denmark[1]: it is 93 m long and is also the tallest church in Denmark with 96 m, with sitting place for around 1200 people, and its building started at the end of the 12th century.

It is unknown exactly when people settled near the mouth the Aarhus River on the coast of Jutland. Certainly in the years 900 there was a Viking town there. Recent research has dated the building of the first city wall to 934. Aarhus was a town of some importance, as there are six runestones in or near the city. Aarhus was called Aros, Arus, Aarhus, or Aars, as early as the 1400s. The city's charter of 1449 names it "Aarss". After the Reformation, the name "Aarhus" became current.

Aarhus' first church, Holy Trinity Church, a timber structure, was built during the reign of Frode King of Jutland around year 900 on a pagan burial site in what was then the center of town. The first bishop was Reginbrand, a missionary bishop of Aros in 948 under the Archbishop of Hamburg. Aros came under the rule of the Archbishop of Viborg in 1060. According to Adam of Bremen, Aros was made a dependent diocese before 998.

St. Nikolai's church was the first cathedral of Aros. The second cathedral was a timber structure built in 1102 by bishop Ulfketil near the present site to house the relics of St. Clement. St. Clement was an early Bishop of Rome who was martyred by having an anchor tied to his neck and thrown into the Black Sea, according to a fictional biography of the saint. Clement was the patron saint of sailors and especially popular in Scandinavia. The first St. Clement's church burned at some point before the 1190s. This timber church was the center of the local veneration of St. Niels of Aarhus (also called St. Nickolas).

St. Niels was a younger son of King Canute VI. As a young man, Prince Niels lost interest in life at court and withdrew to the village of Skibby near Aarhus and built a church with his own hands. He lived a saintly life and helped the people in the area around Aarhus. One day, as he and a few men from the town were felling trees to build the church at Viby near the sea, one of the men complained that he was thirsty. St. Niels prayed for water and a spring appeared to slake the man's thirst; St. Niels's Spring has run ever since. It has been a place of pilgrimage for hundreds of years and many miraculous healings are said to have taken place there, especially on St. John's Day. On his death bed in 1180, St. Niels asked to be buried in "the little church by the sea" (St. Clements). He was buried in the churchyard at St. Clements.

The Aarhus Cathedral The construction of Aarhus Cathedral began in the decade after year 1190, by Bishop Peder Vognsen of the powerful Hvide family from Zealand. Bishop Vognsen built the cathedral around St. Clement's church because local people venerated St. Niels, and Vognsen wanted to harness that devotion for his cathedral. Vognsen also established the cathedral school before the cathedral was completed. The church was finished in 1300 in typical Romanesque style with half-rounded arches supporting a flat timber ceiling. The second St. Clements was built of large red bricks, a new building material that became popular all over Scandinavia and northern Germany for ecclesiastical and public buildings. Four chapels were built into the north transept. The episcopal chair was moved from Our Lady Church to St. Clements.

However, in 1330, the cathedral and much of the town burned down, and the church was abandoned until 1449. By then the Gothic style of architecture had reached Denmark, and the cathedral was enlarged in stages until it reached its present size in year 1500. The nave was lengthened to 93 meters, the longest in Denmark. The transept was widened, and the typical Gothic vaulting raised the ceilings and permitted high windows which fill the building with light.

The Reformation changed life in and around the cathedral in many significant ways. In 1524 Hans Tausen, the Danish Luther, taught a Good Friday sermon at Antvarskov Abbey proclaiming the doctrines of Luther. His superior ordered him imprisoned in the Hospitallers monastery in Viborg, Jutland. Tausen taught from his cell and ordinary people responded with enthusiasm. His superior tried to silence Tausen, but a near riot forced his release. In the beginning, he was allowed to preach in the open air but his supporters broke open a Franciscan church, and soon Tausen had more followers than the church could accommodate. Within a year, he was the king's own chaplain. Luther's ideas quickly spread to Aarhus and soon the townspeople demanded the right to hear the liturgy in Danish. The bishop and canons attempted to stop the spread of the Lutheran doctrine in their diocese, but Tausen had caught the imagination of the people and they would not be cowed by anything the bishop might threaten. Most nobles were staunchly Catholic, and that brought even more support from common people. By 1528 most of the cities had begun the process of reforming their churches. Tausen taught that tearing apart ancient churches was wrong and that orderly change should be used to reform the church.

In 1533 Frederik I died and his son, Christian III was proclaimed King of Denmark at the Viborg Assembly (Danish: Landsting), but the State Council denominated by the Catholic bishops refused to accept the election and called upon count Christopher of Oldenburg to assist in restoring Catholic Christian II to the throne. This resulted in a two-year war called the Count's Feud. Despite the odds, Christian III prevailed and in the summer of 1536 arrested several of the bishops and threw them into prison. The last Catholic Bishop of Aarhus, Ove Bilde, was imprisoned in the summer of 1536 when Denmark officially became a Lutheran nation.

In 1642 lightning struck the tower and set it ablaze, destroying some of the historic bells, but damage to the interior of the church was minimal.