It is believed the name Horsens derives from the old Danish words hors (horse) and næs (headland). From the 12th century the name Horsenes is known.
The earliest traces of a city are remains of a pagan burial site and houses dating back to the 10th century. In the 12th century the kings Sweyn IIIand Valdemar I issued coins in the city. In the 13th century the city got its own legal code.
Excavations have shown that the city was expanded around 1300 with a moat going around the city and its harbour. From the middle of the 19th century industrialisation started and the population rose dramatically when people from the countryside moved to the city to work in the factories. The first Danish iron foundry outside of Copenhagen was opened as well as tobacco and textile factories
