The Mauryan empire was the first and one of the greatest empire to the 4th century BC by Chandragupta Maurya. He organised a powerful army and laid the foundation of a vast empire. He not only overthrew the Nanadas from Magadha, but also theGreek Satraps from the North-West Frontier and unified a large part of India under his centralised government. His successor Bindusara kept the Mauryan empire intact and further extended its boundaries. the reign of Bindusara's son, Ashoka constitutes one of the brightest periods in the Indian jhistory. Ashoka devoted his life to human welfare, after the kalinga war. He considered his subjects as his children. He built many marvels in art and architecture, some of which have survived up to this day. The highest standard and progress in art, literature, culture and civilisation were achieved during this period.