1. Captured by the Mongols, he was succeeded by his brother Jingtai who conferred on him the title Taishang Huang (太上皇), a title reserved for the retired emperors and which he held until 1457.
Zhu Qizhen was the son of the Xuande Emperor Zhu Zhanji and his Empress Sun. He became emperor at the age of eight. At the age of 22 he was imprisoned by the Mongols when he personally directed and lost a battle against the Mongols under Esen Khan. Although he was a prisoner of the Mongols, he became a good friend to the khan. Meanwhile, his brother Zhu Qiyu was installed as the Jingtai Emperor. This reduced Zhengtong's imperial status.
The Zhengtong Emperor was released one year later but when he returned to China, he was put under house arrest by his brother for six years. After the death of his heir apparent, the Jingtai Emperor fell ill and he was deposed by a palace coup which eventually reinstalled Zhu Qizhen as emperor, who called his second reign Tianshun ("heavenly obedience").
Zhengtong's accession at the age of eight makes him the first child emperor of the dynasty hence Zhengtong was easily influenced by others, namely his eunuch Wang Zhen.
The Zhengtong Emperor was released one year later in 1450 but when he returned to China, he was immediately put under house arrest by his brother for almost seven years.
Zhengtong's son (later Emperor Chenghua) was stripped of the title of crown prince and replaced by Jingtai's own son.