As the Amper River would divert into backwaters in several places, there were many fords making it possible to cross the river. The oldest findings of human presence here date back to the Stone Age. The most noteworthy findings were discovered near Feldgeding in the adjoining municipality Bergkirchen. Around 1000 B.C. the Celts arrived in this area and settled. The name �Dachau� originated in the Celtic Dahauua, which roughly translates to �loamy meadow� and also alludes to the loamy soil of the surrounding hills. Some theories assume the name �Amper� river may derive from the Celtic word for �water�. Approximately at the turn of the first millennium the Romans conquered the area and incorporated it into the province of Rhaetia. A Roman trade road between Salzburg and today�s Augsburg is said to have run through Dachau. Remains of this old route are found along the Amper marshlands.
The first known documentation of Dachau was a medieval deed by the Noble Erchana of Dahauua to the Bishop of Freising, both descendants of the lineage of the Aribons. With this deed dating back to August 15, 805 A.D., the Feast of the Assumption of the Blessed Virgin Mary, she donated her entire property in Dachau, including 5 so called Colonenh�fe and some serfs and bondsman, to devolve to the Bishop of the Diocese of Freising after her death.
From the 12th century, Dachau was a summer residence for several Bavarian princes. Between 1240 and 1270, Dachau was granted market privileges, first by Duke Otto II, and then by his son, Duke Ludwig II der Strenge. In 1467 Sigismund, Duke of Bavaria resigned and then kept only Bavaria-Dachau as his domain until his death in 1501.
Between 1546 and 1577, the House of Wittelsbach had the Dachau Palace erected in the Renaissance style. From June 1715 to Autumn 1717, Joseph Effner remodelled the palace to suit the contemporary taste in style.
At the beginning of the 19th century, the castle's north-, east- and south-wing
