The Mauryas: Indian dynasty in the fourth-third centuries BCE, which unified the subcontinent for the first time and contributed to the spread of Buddhism.
In the final weeks of 327 BCE, the Macedonian king Alexander the Great invaded the valley of the river Kabul, and in the next months, he conquered Taxila, defeated the Indian king Porus at the river Hydaspes, and reached the eastern border of the Punjab. He wanted to continue to the kingdom of Magadha in the Lower Ganges valley, but his soldiers refused to go any further, and Alexander was forced to go south. Many Indians now resisted the invaders. By the end of 325, the Macedonian king had left the area of what is now Karachi, and his admiral Nearchus was forced out of Patala.
Alexander's conquests had been spectacular, but he had not conquered India. On the contrary. Not even the Punjab and the Indus valley were safe possessions of his kingdom. Before Alexander had died in 323, he had redeployed nearly all his troops west of the Indus. For the first time, he had lost part of his empire. On the other hand, his invasion changed the course of Indian history. In Taxila, a young man named Chandragupta Maurya had seen the Macedonian army, and - believing that anything a European could do an Indian could do better - decided to train an army on a similar footing. In 321, he seized the throne of Magadha. The Mauryan empire was born.
Chandragupta was a pupil of a famous Brahman teacher, Kautilya. Once Chandragupta had conquered the Nanda throne, he invaded the Punjab - and he was lucky. In 317, one of Alexander's successors, Peithon, the satrap of Media, tried to subdue the leaders of the eastern provinces, who united against him. This civil war offered Chandragupta the opportunity he needed and he was able to capture Taxila, the capital of the Punjab.
When the situation in Alexander's former kingdom had stabilized, one of his successors, Seleucus, tried to reconquer the eastern territories, but the war was inconclusive, and the Macedonian offered a peace treaty to Chandragupta. The latter recognized the Seleucid Empire and gave his new friend 500 elephants; Seleucus recognized the Mauryan empire and gave up the eastern territories, including Gandara and Arachosia (i.e., the country northeast of modern Qandahar). Finally, there was epigamia, which can mean that either the two dynasties intermarried, or the unions of Macedonians/Greeks with Indians were recognized.
Chandragupta had now united the Indus and Ganges valley - a formidable empire. There was a secret service, there were inspectors, there was a large army, and the capital at Patna became a beautiful city. His adviser Kautilya wrote a guide to statecraft which is known as Arthasastra. A Greek visitor, Megasthenes, gives a very strange description of the caste system (accepting seven instead of the usual four classes of people), and it is likely that he describes an attempted reform. This is certainly not impossible, because Chandragupta turned out to be not deeply attached to orthodox Brahmanism. According to the ancient scriptures of the Jainists, the king abdicated at the end of his life (in 297?) in favor of Bindusara, and converted to the Jaina faith; he died as an ascetic, having fasted to death.
Bindusara was the son of Chandragupta. His reign lasted a quarter of a century, until 272, but of the three great Mauryan emperors, he is the least known. For example, he is mentioned as the man who conquered "the country between the two seas" (i.e., the Bay of Bengal and the Arabian Sea), which suggests that he conquered central India, but the same deeds are ascribed to his son Ashoka. We can not choose between these two.
Bindusara had some contacts with the far west, where Antiochus I Soter had succeeded his father Seleucus as king of the Seleucid empire. Bindusara approached him, asking for wine, figs, and a philosopher - the king sending him only the two first products, saying that philosophers were not fit for export. Whatever one thinks about this anecdote, it proves that there were diplomatic contacts. It comes as a surprise, therefore, that Bindusara is called Amitrochates in Greek sources, which simply can not be a rendering of Bindusara's name. A possible explanation is that Bindusara had accepted a throne name Amitragatha, 'destroyer of enemies'. Possible. But why isn't this mentioned in Indian sources? This king remains a mystery.
Texts from southern India mention the Mauryan chariots invading the country "thundering across the land, with white pennants brilliant like sunshine". Indeed, Ashoka, who succeeded his father Bindusara in 272, was a great conqueror, and the first to unite the Indian subcontinent, except for the extreme south. However, the emperor came to hate war after he had seen the bloodshed of the conquest of Kalinga in eastern India, and he converted to Buddhism. He wanted to establish dhamma, 'the law of justice', everywhere in India and Arachosia. In the rock edicts he left behind on several places in his realm, the emperor says:
The beloved of the gods [...] conquered Kalinga eight years after his coronation. One hundred and fifty thousand people were deported, one hundred thousand were killed and many more died from other causes. After the Kalingas had been conquered, the beloved of the gods came to feel a strong inclination towards the dhamma, a love for the dhamma and for instruction in dhamma. Now the beloved of the gods feels deep remorse for having conquered the Kalingas.
Indeed, the beloved of the gods is deeply pained by the killing, dying and deportation that take place when an unconquered country is conquered. But the beloved of the gods is pained even more by this -that Brahmans, ascetics, and householders of different religions who live in those countries, and who are respectful to superiors, to mother and father, to elders, and who behave properly and have strong loyalty towards friends, acquaintances, companions, relatives, servants and employees- that they are injured, killed or separated from their loved ones. Even those who are not affected by all this suffer when they see friends, acquaintances, companions and relatives affected. These misfortunes befall all as a result of war, and this pains the beloved of the gods.
It seems that Ashoka was sincere when he proclaimed his belief in ahimsa (non-violence) and cooperation between religions ("contact between religions is good"). He never conquered the south of India or Sri Lanka, which would have been logical, and instead sent out missionaries -as far away as Cyrenaica- to convert others to the same beliefs, and sent his brother to Sri Lanka. He erected several stupas, founded Buddhist monasteries, softened the harsh laws of Bindusara and Chandragupta, forbade the brutal slaughter of animals, and organized a large Buddhist council at Patna, which had to establish a new canon of sacred texts and repress heresies.
After the death of Ashoka, the Mauryan empire declined. In c.240, the Bactrian leaders -who were of Greek descent- revolted from their Seleucid overlords, and although king Antiochus III the Great restored order in 206, the Bactrian leader Euthydemus declared himself independent within a decade. Not much later, the Graeco-Bactrian kingdom expanded into Drangiana and Gandara.
The invasion of the Punjab, which took place in 184, revitalized the Greek culture in the region south of the Hindu Kush mountain range, where Euthydemus' son Demetrius created a new kingdom, consisting of Gandara, Arachosia, the Punjab and even a part of the Ganges valley. Demetrius died in c.170 and left his kingdom to his sons, who continued to fight against the Mauryan empire. However, they were divided. But when king Menander reunited the Indo-Greek kingdom in c.135, the westerners were able to invade the heartland of the already contracted Mauryan empire, and even captured Patna. Never has a Greek army reached a more eastern point.
Yet, the Indo-Greek kings had to accept the realities created by the Mauryan empire. Buddhism was to be the religion of the future. King Menander converted and became something of a Buddhist saint. One of the sacred texts of Buddhism is called Milindapañha, "Questions of Menander".