The Děčín (Tetschen) area was settled by the Slavic tribe of the Děčané in the 9th century, whence its name. In the 10th century the Přemyslid dukes of Bohemia had a fortress built on the left bank of the Elbe ford, but after a flood it was rebuilt on the right bank in 1059. A settlement on the trade route from the Ore Mountains in the west to the adjacent Upper Lusatia region was first mentioned in a 993 deed. King Ottokar II of Bohemia (1253–1278) had the town of Děčín laid out as an administrative centre of the surrounding estates after calling in German settlers. The population, history and culture stayed German until their expulsion in 1945.
It was under the control of the Lords of Wartenberg from 1305 until 1534, when it was bought by the rich Lord Rudolf von Bünau. This family introduced Protestantism to the region and the town flourished; however the Protestant belief was suppressed by the Habsburg kings in the course of the Counter-Reformation, and the Bünaus were driven out upon the 1620 Battle of White Mountain. In 1628 they sold the town to the Barons of Thun, it was devastated several times during the Thirty Years' War.
In the 18th century, Tetschen followed fashion and became a spa town under Baron Johann Joseph Thun, who searched the area for a suitable spring and found one in the nearby village of Horní Žleb (Obergrund) in 1768. The centre of a busy trading hub was not, however, the ideal place to build a spa, and the idea was eventually dropped in 1922; today the town's spa past has been largely forgotten. Nevertheless, the Elbe Valley railway line was completed in 1851, which promoted the development on the left bank of the river. Soon, neighbouring Boden bach (Podmokly) grew bigger than Tetschen and received town privileges in 1901. Upon the 1938 Munich Agreement, both towns were annexed by Nazi Germany, incorporated into the Reichsgau Sudetenland and merged in 1942. After World War II the German population was
