One of Baku`s most important monuments is the fortress walls known as protection fortification, dated back to many centuries which survived until today, protected Baku from the attacks by foreign invaders. The fortress walls are an evidence of the material culture of the Azerbaijani people. According to the three-line stone inscription found during the restoration of the fortress wall in 1950-1954 that the city wall of Baku was built by Shirvanshah III Manuchohr the XII century (1120-1160). This stone inscription, which is considered to be a very valuable document for the ancient history of Baku, is currently being kept in the fund of the National History Museum of Azerbaijan.