Which king ascended the throne the earliest in Vietnamese history, was murdered by his brother at the age of 18?

Le Dynasty

The Le Dynasty had a total of 26 kings. Of which, the Early Le Dynasty had 10 kings and the Later Le Dynasty had 16 kings. This was the feudal dynasty that had the most kings in Vietnamese history. The 10 kings of the Early Le Dynasty belonged to 6 generations: Le Thai To, Le Thai Tong, Le Nhan Tong, Le Thanh Tong, Le Hien Tong, Le Tuc Tong, Le Uy Muc, Le Tuong Duc, Le Chieu Tong and Le Cung Hoang. This was the period when the Le Dynasty kings held all the power, and was also the great, golden age of the Vietnamese feudal regime. Some documents record that the Early Le Dynasty had 11 kings. The remaining king mentioned was Le Nghi Dan, who ascended the throne after overthrowing Le Nhan Tong. But less than a year later, he was overthrown by his mandarins because they thought he was incompetent and had committed treason. After being overthrown, he was demoted to Le Duc Marquis and history books often do not consider him the legitimate monarch of the Later Le Dynasty. The 16 kings of the restored Le Dynasty include: Le Trang Tong, Le Trung Tong, Le Anh Tong, Le The Tong, Le Kinh Tong, Le Than Tong, Le Chan Tong, Le Huyen Tong, Le Gia Tong, Le Hy Tong, Le Du Tong, Le De Duy Phuong, Le Thuan Tong, Le Y Tong, Le Hien Tong and Le Man De (Le Chieu Thong).

Source: https://vtc.vn/vi-vua-nao-len-ngoi-som-nhat-su-viet-18-tuoi-bi-anh-trai-sat-hai-ar761343.html