Hildesheim, one of the oldest cities in the North of Germany, became the seat of the Bishopric of Hildesheim in 815 and may have been founded when the bishop moved from Elze to the Innerste ford, where it was an important market on the Hellweg trade route. The settlement the cathedral very quickly developed into a town which was awarded market rights by King Otto III in 983. Originally the market was held in a street called Old Market (Alter Markt) which still exists today. The first market place was laid out around Saint Andrew's Church. When the city grew further, a bigger market place became necessary. The present market place of Hildesheim was laid out at the beginning of the 13th century when the city had about 5,000 inhabitants. When Hildesheim obtained city rights in 1249, it was one of the biggest cities in Northern Germany. For four centuries the clergy ruled Hildesheim, before a city hall was built and the citizens gained some influence and independence. Construction of the present City Hall started in 1268. In 1367 Hildesheim became a member of the Hanseatic League. A war between the citizens and their bishop cost dearly in 1519-1523 when they engaged in a feud. Hildesheim became protestant in 1542, and only the cathedral and a few other buildings remained in imperial (catholic) hands. Several villages around the city remained catholic as well. In 1813, after the Napoleonic Wars, the town became part of the Kingdom of Hanover, which was annexed by the Kingdom of Prussia after the Austro-Prussian War in 1866 as a province. In 1868 a highly valuable trove of about 70 Roman silver vessels for eating and drinking, the so-called Hildesheim Treasure, was unearthed by Prussian soldiers.
During World War Two, Hildesheim was chosen (based on its inhabitants devotion to Adolf Hitler) to be the indoctrination and further training location for a group of 27 British Prisoner of war defectors as members of what was known as the "British Frei Korps" SS
