When King Mindon became in ill health and could not manage state affairs since August 1878, all the high-level ministers took an oath to the king and the one to whom he pointed. Queen
Hsinbyumashin essentially controlled the nation at the time under her husband's name. As all three of her children were female, she conspired with the prime minister,
Kinwun Mingyi U Kaung, to secure the succession for
Prince Thibaw, who was in love with her middle daughter,
Supayalat. U Kaung also hoped to introduce a constitutional monarchy if Thibaw succeeded to the throne. Under the guise that King Mindon wanted to bid his children farewell,
Hsinbyumashin had all royals of close age who could potentially be heirs to the throne seized and thrown into prison by edict on 11 September 1878. Hsinbyumashin summoned every member of the imperial family to the Mandalay Palace without weapons to meet Mindon Min. While they were waiting to see the king, an armed group led by
Maung Maung Toke arrested them. Hsinbyumashin's secret mission was leaked to the second
Queen of the Northern Gilded Chamber who made her two sons, and Nyaungoak Prince, escaped and slipped away to India via British ambassador Colonel Duncan. On 19 September 1878, Hsinbyumashin and her accomplices discussed, and a proclamation making Prince Thibaw the crown prince was announced, without informing the king. When the king knew the circumstances within a week because of
Limban Mibaya,
Thetpan Mibaya,
Khonnaywa Mibaya and the second Queen of the Northern Gilded Chamber who informed him the situation, they all were released and the king appointed
Thonze Prince,
Mekkhaya Prince and Nyaungyan Prince as the governors of
Chindwin Province,
Taungdwingyi Province and Lower Myitsin Province respectively. But, together with some relatives, they were arrested again the following day. This time, Hsinbyumashin made no one entered the king's chamber, and the Queen of the Southern Apartment,
Seindon Mibaya, Lepanzin Mibaya,
Tharazein Mibaya, Lècha Mibaya, Ngazon Mibaya, Thanazarit Mibaya and Palepa Mibaya looked after the king. King Mindon died on 1 October 1878, and King Thibaw ascended the throne after two days. ==Events==