Although he is best remembered for his empire building, Bayinnaung's greatest legacy was his integration of the Shan states into the Irrawaddy-valley-based kingdoms. After the conquest of the Shan states in 1557–1563, the king put in an administrative system that reduced the power of hereditary Shan "saophas", and brought Shan customs in line with low-land norms. It eliminated the threat of Shan raids into Upper Burma, an overhanging concern to Upper Burma since the late 13th century. His Shan policy was followed by Burmese kings right up to the final fall of the kingdom to the British in 1885.