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.[2]
He could not replicate this administrative policy everywhere in his far flung empire, however. His empire was a loose collection of former sovereign kingdoms, whose kings were loyal to him as the Cakkavatti (Universal Ruler), not the Kingdom of Toungoo. Indeed, Ava and Siam revolted just over two years after his death. By 1599, all the vassal states had revolted, and the Toungoo Empire completely collapsed.
He is considered one of the three greatest kings of Burma, along with Anawrahta and Alaungpaya. Some of the most prominent places in modern Myanmar are named after him. He is also well known in Thailand as Phra Chao Chana Sip Thit (พระเจ้าชนะสิบทิศ, "King of the Ten Directions").