After the Romans left Günzburg in the fifth century, the Alamanni tribe settled there. In around 700 the nearby castle of Ricinis was mentioned by the Cartographer of Ravenna as one of the five most important castles of Alemannia. In 1065 first documentary evidence appears of the town itself as Gunceburch. In 1301 the town became part of the Habsburg house and was developed into the centre of the Margraviate of Burgau; for a time (1803–1805) it was even the capital of all Further Austria.
After the construction of a castle and church in the south-western corner of the upper town (1577/80), Günzburg became the residence of Archduke Ferdinand II`s son Karl from 1609 until 1618. Margrave Karl was able to bring craft and trade to new heights, but later all his efforts were ruined by the Thirty Year War (1618–1648) in the course of which the number of Günzburg`s citizens went down from about 2,400 to some 800. The castle went up in flames (1703) and the citizens suffered badly under the occupation.
Today the the margraves' castle is the main tourist attraction. It is the only Habsburg castle built in Germany.
References:The first written record of church in Danmark locality date back to the year 1291. Close to the church are several stones with a Christian text and cross inscribed. The oldest parts of the present red-brick church are from the 1300s. In the late 1400s the church was enlarged to the appearance it has today. The church has been modified both internally and externally several times, among other things after the fires in 1699 and 1889. There are lot of well-preserved mural paintings in the walls.