THE SELEUCID AND GRAECO-BACTRIAN PERIODS (4th-2nd centuries B.C.)
In its expansion to West, the Achaemenids Empire confronted finally with the Greek states. In 334 B.C. Alexander the Great started a war against the Achaemenids, which culminates with his victory in 331 B.C. This victory opened the way to the heart of Achaemenian Empire and by 330 B.C. Alexander had captured the Southern Bactria (now North Afghanistan). In spite of the efforts of the local population to resist, Alexander went on to capture all Bactria, Sogdiana and Parthia which became parts of the vast new Greek empire.
According to ancient texts, Alexander built from 8 to 12 cities, each called Alexandria, in Bactria and Sogdiana in order to consolidate his dominance over Central Asia. However, all efforts to create a single state failed and his Empire started to disintegrate immediately after his death in 323 B.C. A bitter struggle for power ensued between his successors. Seleucus, one of Alexander’s leading commanders who had consolidated the empire in Babylon in 312-311 B.C. began to lay the foundations of the Seleucid Empire which ruled over a vast territory, spreading from the Mediterranean Sea to India. With enemies both external and from within his ranks, it was difficult to maintain control in all territories.
Bactria, which was the furthest most eastern province of the Seleucid Empire, was the first to break from its dominance. So in around 250 B.C. Graeco-Bactrian (250-128 B.C.) kingdom was born. It comprised Bactria, Sogdiana, Margiana and other regions. At its peak, around 190-180 B.C. Afghanistan and northwest India were also included. The demise of this short-lived empire was prompted by internecine wars, civil unrest and nomadic invasions.
Large number of Greeks remained in Central Asia during Seleucid rule, in the cities and settlements built by Alexander, resulting in a process of mutual influence and cultural fusion of Hellenistic and local art traditions. These interactions continued during the Graeco-Bactrian period as well. Nowhere is this phenomenon more clearly evident than in the Temple of the Oxus at the site of Takhti Sangin (Qubadiyon district, Khatlon oblast) and also at the sites of Saksanokhur (Farkhor district, Khatlon oblast), Khushdilon (Dangara district Khatlon oblast).
The oldest cultural layers relating to the Graeco-Bactrian times were found at the site of the hill fort of Dushanbe situated in the Hissar valley, in the territory of Dushanbe, the capital of Republic of Tajikistan. In the north of Sughd oblast, in the citadel of ancient Khujand, sections of the walls dating from the 6th-2st centuries B.C. were found. The wall and the cultural layers relating to the 4th to 2nd centuries B.C. were found. Materials dating from the 5th to 4th centuries B.C. were also found in the lower layers of the main cemetery of Kurkat oasis, in the site of Shirin.
 Also known as Alexander of Macedon