In the 14th and 15th centuries, Ava fought wars of unification but could never quite reassemble the lost empire. Having held off Ava, the Mon-speaking Hanthawaddy entered its golden age, and Arakan went on to become a power in its own right for the next 350 years. In contrast, constant warfare left Ava greatly weakened, and it slowly disintegrated from 1481 onward. In 1527, the Confederation of Shan States conquered Ava and ruled Upper Myanmar until 1555.