 Thăng Long was renamed Đông Đô, Eastern Capital.Although widely blamed for causing national disunity and losing the country later to the Ming Empire, Hồ Quý Ly's reign actually introduced a lot of progressive, ambitious reforms, including the addition of mathematics to the national examinations, the open critique of Confucian philosophy, the use of paper currency in place of coins, investment in building large warships and cannons, and land reform.He ceded the throne to his son, Hồ Hán Thương, in 1401 and assumed the title Thái Thượng Hoàng, in similar manner to the Trần kings.