Turda's salt deposit has been known and exploited by ancient times, but it was put into systematic operation of the deposit, by underground mining work, during the Roman conquest in Dacia.
The salt was exploited in rooms of 17-34m (56-112 feet) depth and 10-12m (33-39 feet) width, disposed one near the other an separated by a safety consolidation. This system ensured a massive extraction of the salt, but it worked only in those areas where the salt was exploited near the surface. Salt was continuously extracted during the 6 and 9 century, along with other very useful minerals.
The Salt Customs in Turda are mentioned for the first time in 1075 a.d. During the 13 century, Turda's salt mine is mentioned in official documents at the 1st of May 1271, when the mine was offered to the Catholic Church's Transilvanian leaders. These and the bishop of Transilvania subsequently, would get privileges for using the salt from the mine in Turda. (full article, source)
Transylvania (Romanian: Ardeal or Transilvania; Hungarian: Erdély; German: De-Siebenbürgen.ogg Siebenbürgen (help·info), see also other denominations) is a historical region in the central part of Romania. Bounded on the east and south by the Carpathian mountain range, historical Transylvania extended in the west to the Apuseni Mountains; however, the term frequently encompasses not only Transylvania proper, but also the historical regions of Crişana, Maramureş, and (Romanian) Banat.Transylvania was once the nucleus of the Kingdom of Dacia (82 BC–106 AD). In 106 AD the Roman Empire conquered the territory and after that its wealth was systematically exploited. After the Roman legions withdrew in 271 AD, it was overrun by a succession of tribes, which subjected it to various influences. During this time areas of it were under the control of the Visigoths, Huns, Gepids, Avars and Bulgars. Thereafter the Romanized Dacian inhabitants either moved into the mountains and preserved their culture or migrated southward. It is likely that elements of the mixed Daco–Roman population held out in Transylvania. There is an ongoing scholarly debate over the population of Transylvania before the Hungarian conquest (see Origin of the Romanians).The Magyars conquered the area at the end of the 9th century and firmly established their control over it in 1003, when their king Stephen I, according to legend, defeated the native prince entitled or named Gyula. Between 1003 and 1526, Transylvania was a voivodeship of the Kingdom of Hungary, led by a voivod appointed by the Hungarian King. After the Battle of Mohács in 1526 Transylvania became effectively an independent principality ruled primarily by Calvinist Hungarian princes. Afterward, in 1566, Hungary was divided between the Habsburgs and the Turks, with the Transylvanian principality maintaining autonomy as an Ottoman subject.The Habsburgs acquired the territory shortly after the Battle of Vienna in 1683. The Habsburgs, however, recognized the Hungarian sovereignty over Transylvania,[dubious – discuss] while the Transylvanians recognized the suzerainty of the Habsburg emperor Leopold I (1687), and the region was officially attached to the Habsburg Empire, separated in all but name from Habsburg controlled Hungary and subjected to the direct rule of the emperor’s governors. In 1699 the Turks legally conceded their loss of Transylvania in the Treaty of Karlowitz; however, anti-Habsburg elements within the principality only submitted to the emperor in the 1711 Peace of Szatmár. After the Ausgleich of 1867 the region was fully reabsorbed into Hungary  as a part of the newly established Austro-Hungarian Empire.Following defeat in World War I, Austria-Hungary began to disintegrate. The ethnic Romanian majority elected representatives, who then proclaimed union with Romania on December 1, 1918. In 1920, the Allies confirmed the union in the Treaty of Trianon. Hungary protested against the detach, as over 1,600,000 Hungarian people were living in the area in question, mainly in Szekler Land of Eastern Transylvania, and along the newly created border, which was drawn through areas with Hungarian majority. In August 1940, in the midst of World War II, Hungary regained about 40% of Transylvania by the Vienna Award, with the aid of Germany and Italy. The territory, however, reverted to Romania in 1945; this was confirmed in the 1947 Paris Peace Treaties.In distant regions, Transylvania is also often associated with Dracula (Bram Stoker's novel and its film adaptations), and the horror genre in general, while in countries of Central and Eastern Europe the region is known for the scenic beauty of its Carpathian landscape and its rich history.