The Timok region is one of mountains, rich forests, and abundant water, especially mountain springs and streams. It is these waters that in many ways define which hills and valleys belong to Timok. Settlements always arise where there is abundant water, and Knjaževac is one of these. It is located in the valley of the Beli Timok (White Timok), which together with the waters of the rivulets Svrljiški Timok and Trgoviški Timok join the Crni Timok (Black Timok) river at Zaječar, forming the Great Timok (Veliki Timok, or simply Timok). The valley of the Beli Timok is conducive to agriculture and viticulture, while the surrounding mountains are ideal for the farming of sheep and goats, as well as for walnut groves. The mountains offered protection, but also created isolation.
In a corner bounded by the Sava and the Danube, three centuries before the common era, Celts found the abandoned settlement of a Thracian tribe, the Singi. Recognizing its strategic advantages and abundance of resources, they settled there. A fortress arose, in Celtic dun, and Singidunum was born. It was home to Celts, Romans and Byzantines for a millenium before the Slavs arrived. Seeing the pale limestone palisades in the distance, they called it the White City – Beo Grad. It became part of the kingdom of King Dragutin Nemanjić in the 13th century, and flourished under Stefan Lazarević in 15th century. It fell into Hungarian hands, setting into play a back-and-forth struggle between the Kingdom of Hungary and the Ottoman Empire that went on for centuries. In 1594 as a reprisal for a Serbian uprising, Albanian Ottoman vezier Sinan Paša ordered the public burning of St. Sava’s relics on Vračar hill. The warring continued until Karađorđe liberated it on St. Andrew’s day 1807. The failed first rebellion led to notable migration of Serbs out of the region in 1813, and it took decades for the city to earn its place as capital of the Principality and Kingdom of Serbia.