History of Bolivia to 1809 reduction in silver output. After 1700 only small amounts of bullion from Upper Peru were shipped to Spain. Kings from the Bourbon Dynasty in Spain tried to reform the colonial economy in the mid-eighteenth century by reviving mining. The Spanish crown provided the financial support necessary to develop deeper shafts, and in 1736 it agreed to lower the tax rate from 20 to 10 percent of the total output. The crown also helped create a minerals purchasing bank, the Banco de San Carlos in 1751 and subsidized the price of mercury to local mines. The foundation of an academy of
Kalhora dynasty agents or governors. Later he extended his rule to Sehwan and Bukkur and became sole ruler of Northern and central Sindh except Thatto which was still under administrative control of Mughal Empire. The Kalhora dynasty produced four powerful rulers namely, Mian Nasir Muhammad, Mian Yar Muhammad, Mian Noor Muhammad and Mian Ghulam Shah. Kalhora dynasty The Kalhora dynasty or Kalhoro dynasty () was a Sunni Muslim Sindh dynasty of "sindhis tribe origin. which ruled the Sindh and other parts of present-day Pakistan from 1701 to 1783. The family line is rooted in the Kalhora clan. They were assigned to hold