Nadir Shah's real name was Nadir Quli. In 1736, after the death of the last Persian Sultan, Nadir became the ruler of Persia and assumed the title traditionally adopted by the Persian monarch, that of 'Shah'.
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In a bid to expand his territory, he conquered **Kandahar** before shifting his attention to **India**. He was aware of the chaotic political conditions prevailing in India, and inefficiency of the **Mughal** ruler. He invaded India in 1739. He defeated the Mughal army in the **battle of Karnal** in February 1739. Muhammad Shah was taken prisoner and Delhi came under the control of Nadir Shah. He plundered Delhi's enormous wealth. The Persian troops left Delhi in May 1739, but took with them wealth then worth Rupees 70 crores, the fabulous *KOHINOOR* diamond and the priceless Peacock throne, which thereafter served as a symbol of Persian might.
This left the Empire open to the threat of inversions from the north-west. In the meantime, **the Marathas** has emerged as the prominent power in the country.