Describe Mahmud of Ghazni's motives for invading India and the impact of his campaigns.

Mahmud of Ghazni had dual motives for invading India: plundering temple wealth accumulated over centuries and spreading his version of Islam by destroying non-Muslim places of worship. His campaigns involved destruction, civilian slaughter, and capture of prisoners sold as slaves in Central Asia. Whilst he did not establish permanent rule beyond Punjab, his invasions caused Indian sciences to retreat to safer places like Kashmir and Varanasi.