The history of the fortress
Georg Krauss (or Georgius Krauss or Georg Kraus) (1607-1679) reports that in 1191 the place where Sighisoara is now, was inhabited, but the first documentary attestation of the settlement dates back to 1280 under the name of Castrum Sex. In 1298 the German name Schespurch (later "Schäßburg") was mentioned. The town is mentioned in 1367 as "civitas" (city). The Romanian name of the city is certified in writing since 1435. The "Sighişoara" form entered Romanian on the Hungarian branch, being an adaptation of the name "Segesvár".

Fortress strengthening
During the years, the Sighisoara fortress was not exempted from vicissitudes,
the first was the great tatar raiding of 1241, while the fortress was still not fortified.
The construction of the city wall, which is 950 m long, began in 1350.
The initial height was 4 m, but in the XVth century it was raised by another 3-4 m.
It had 14 towers (each belonging to one guild) and 4 bastions.
  There are now 9 towers and three bastions, the most representative of which is the Clock Tower (Tower of Hours).
Attacks in the Fortress and the fire in 1676
Between 1431 and 1435 Vlad Dracul stayed in Sighisoara, waiting for the right moment to climb on the trone of the Romanian Country. He also ruled these regions in the name of Sigismund of Luxembourg, King of Hungary. It seems that during this period (in 1431) Vlad Tepes was born in Sighisoara.
In 1600, the fortress is attacked by the troops leaded by Michael the Brave and later attacked and slaughtered by the bands led by General Basta, but people are get away with their lives by paying 50,000 redemption, "borrowed money," as chronicler Krauss. In 1646, 2.000 inhabitants died of plague, and in 1709 the number of victims was 4.000. In 1676 the city was almost destroyed by a strong fire (624 houses, 7 defensive towers, the Monastery Church,). In 1788 was a conflagration again.
Between 1703-1711 there is the anti-Habsburg movement in Hungary and Transylvania. The Curuti (anti-Habsburgs) - led in the region of Tarnavelor by Vasile Neagu and Bucur Campeanu - attacked the Sighisoara fortress which was seen as being on the side of the lobontii (the defenders of the Habsburg empire). After heavy fighting, the Curuti realize that they can not occupy the city, and they retreat.
Source: Wikipedia
XIXth century
In 1849 the city was occupied by the Forró-led troops, and later on again occupied by the troops led by Józef Bem.
Through the battle between the Tarsus interventionist troops and the Hungarian revolutionary army on the plain between Sighisoara and Albesti on July 31, 1849, Sighisoara entered into the history of the revolutionary struggles of the XIXth century. In this battle died, among others, the Hungarian poet Sándor Petőfi.
In the interwar period Sighisoara was the seat of Tarnava Mare County.
Source: Wikipedia