Ummayyad ruler Hajjaj Bin Yusuf sent his Nephew, General Muhammad Bin Qasim, to rescue pilgrims who had been captured when Raja Dahir's forces from Sindh, Indus River Valley, attacked their ship. Muhammad Bin Qasim conquered Sindh introducing Islam to South Asia and giving Sindh the title of Bab-ul-Islam (The Gateway of Islam). He ended unjust treatment of the so-called 'untouchable caste' and incorporated the ruling class in his administration to establish law and order in the region.