sentences:  He extended Aceh's effective control southward at just the time when the Dutch were consolidating their holdings northward.Britain, heretofore guarding the independence of Aceh to keep it out of Dutch hands, re-evaluated its policy and concluded the Anglo-Dutch Treaty of Sumatra, which allowed for Dutch control throughout Sumatra in exchange for concessions in the Gold Coast and equal trading rights in northern Aceh.The treaty was tantamount to a declaration of war on Aceh, and the Aceh War followed soon after in 1873, with the Dutch making the unfounded excuses that Aceh was sponsoring piracy and preparing to conclude a treaty with the United States.