According to classical historical records, Chandragupta Maurya first emerged in the panorama of Indian politics on the threshold of the invasion of the Macedonian king Alexander in 326 B.C. The entire northwestern India at that time reduced into the feudatory of Alexander. Consequently the task of liberating the whole of northwestern India from the yoke of the alien rule was not an easy job for Chandragupta Maurya. But as the historical records suggest, Chandragupta was successful in freeing the entire northwestern part of India from the bondage of the Macedonian king Alexander.
Strangely enough all the indigenous sources are silent about Chandragupta`s war and conquest against the Greeks. Therefore knowledge about the conquest of Chandragupta in the liberation war of the Greeks is limited to the classical sources of the contemporary era. Bongard Levin, the celebrated historian of modern times, holds that- to the Indians Chandragupta`s war against the Greek was a phase of his ultimate struggle against the Nandas and that is why they might not have put enough emphasis on his campaign against the Greeks. According to Levin, Chandragupta, used his conquest against the Greeks as his step to achieve an exclusive authority over north India. Regarding the nature of the war of liberation against the Greeks, historians have come up with pretty many interpretations. Justin provides the generally accepted interpretation. According to Justin, Chandragupta after his victory abused the term "freedom" and in this point Chandragupta`s campaign of liberation war against the Greeks contradicts the ideological interpretation of the liberation war. Thus to Justin, Chandragupta Maurya was no less an imperialist than the Greeks who reduced his subjects to accept his slavery. Whatever the motive of Chandragupta was behind the liberation war, the victory against the Greeks wiped out the effects of Alexander`s victory in the battle of Hydaspes.
Chandragupta was a shrewd diplomat and most of his conquests are the outcome of this astute diplomacy. He set out for the conquest against the Greeks taking advantage of the protest of the native people against the Greek satraps, who were exercising their control in the areas where the Macedonian garrison was posted. During these circumstances the Greek Satraps Nicanor and Philoppos were assassinated. To top it all, the sudden death of Alexander created a vacuum in the entire political scenario. Moreover the quarrel among Alexander`s generals, as a result of his death weakened the position of the Greeks in India. Chandragupta did not let loose the advantage of Indian unrest against the Macedonian rule and mobilised a huge army under his leadership to uproot the Greeks.
The records of the classical writers are relevant regarding the conquest of Chandragupta against the Greeks. They have presumed that Chandragupta might have occupied Sind from the Macedonians, initially. This fact is indirectly supported by the information that when the generals of Alexander divided his empire prior to the Partition treaty of Triparadicus in 321 B.C., they did not mention Sind. Therefore the historians have mentioned that perhaps the territory of Sind was lost to the Greeks. Moreover the fact that Chandragupta made Lower Sind the base of his operation against the Greeks in 321 B.C. is backed up historically, which indicates that Sind was not under the sway of the Greeks. After the successful campaigning against the Greeks in Sind, Chandragupta set out for the conquest of East Punjab. Chandragupta entered east Punjab without any formidable opposition because King Porus, the vassal chief of Alexander was assassinated by the Greek general Eudemus and the latter fled from India. Thus Chandragupta became the master of the entire region of Punjab around the areas of Jhelum without much struggle.
From the accounts of Pliny the fact is supported that, Chandragupta, after conquering the entire Sind and East Punjab crusaded for west Punjab up to the Indus River. To the classical writers the extended region of Indus formed the boundary between the territories of Chandragupta Maurya and Selucus Niketar, before the two kings came to blows. However Chandragupta managed to conquer the territory of west Punjab from the outlander Greeks. Consequently with the acquiring of west Punjab the entire northwestern part came under the sway of Chandragupta Maurya.
The great achievement of Chandragupta Maurya has been eulogised in the verses of Mudrarakshasha, which is one of the indigenous extant authentic records of the reign of Chandragupta Maurya.