Turda is a city and Municipality in Cluj County, Romania, situated on the Arieş River.
Founded as a Dacian city under the name Patavissa or Potaissa (most frequently confirmed), Turda was conquered by the Romans. The castrum established was named Potaissa too and became a municipium, then a colonia. Potaissa was the basecamp of the Legio V Macedonica from 166 to 274.
Salt mines were worked in the area since prehistoric times. After the Hungarian conquest, the Turda salt mines were first mentioned in 1075. (The salt mines were closed in 1932 but have recently been reopened for tourism.)
Saxons settled in the area in the 11th century. The town was destroyed during the Tartar invasion in 1241-1242. Andrew III of Hungary gave royal privileges to the settlement. These privileges were later confirmed by the Angevins of Hungary.
The Hungarian Diet was held here in 1467, by Matthias Corvinus. Later, in the 16th century, Turda was often the residence of the Transylvanian Diet, too. The 1558 Diet of Turda declared free practice of both the Catholic and Lutheran religions. In 1563 the Diet also accepted the Calvinist religion, and in 1568 it extended freedom to all religions, declaring that "It is not allowed to anybody to intimidate anybody with captivity or expelling for his religion" – a freedom unusual in medieval Europe. This Edict of Turda is the first attempt at legislating general religious freedom in Christian Europe (though its legal effectiveness was limited).
In 1609 Gabriel Báthori granted new privileges to Turda. These were confirmed later by Gabriel Bethlen. In the battle of Turda, Ahmed Pasha defeated George II Rákóczi in 1659.
In 1944, the Battle of Turda took place here, between German and Hungarian forces on one side and Soviet and Romanian forces on the other. It was the largest battle fought in Transylvania during World War II.