 Complete the following phrase:  The oldest documented reference to the city Parvomay of 1576 it is in the register of Ottoman Taxes in Bulgaria. In 1671 the famous Turkish travel writer Evliya Celebi mentions Village Iskra to the South. Parvomay was for a time part of Eastern Rumelia an autonomous province within the Ottoman Empire after the Treaty of Berlin in 1878. After the revolution of September 6, 1885, the province was annexed by the Principality of Bulgaria. On 14 April 1928, a 