India has had united empires 4-5 times. 300 BC Maurya Empire which beat Alexanders invasion and converted India from Hinduism to Buddhism. Gupta empire around 1000 AD which reconverted India from Buddhism to Hinduism. Delhi Sutantanate around 1200-1400 which got most of India except the South together along with Afghanistan, introduced Islam, Mughal empire around 1500-1600 which took over from Delhi Sultanate, Maratha empire around 1700 which got most of central and Northern India together. British raj was actually pretty disunited as only about 40% of the land area was under direct british rule with 500+ independent kingdoms which had a tributary relationship to the British. Modern India was created between 1947 and 1960 by slowly absorbing sometimes diplomatically sometimes by force of arms these 500 kingdoms.