In 1421, Xia Yuanji was imprisoned for voicing his opposition against the Yongle Emperor's decision to undertake the third Mongol military campaign, which would add another expenditure to the existing ones.[1]
After the advice of Xia Yuanji, the Hongxi Emperor ordered the cessation of the Ming treasure voyages on 7 September 1424, the day of his accession to the throne.[2] On 8 September 1424, he released Xia Yuanji from his imprisonment.[3] When the succeeding Xuande Emperor ordered the seventh voyage, he went against the general court opinion.[4] This was after the death of Xia Yuanji, a prominent critic of the maritime expeditions, on 19 February 1430.[5]
Chan, Hok-lam (1998). "The Chien-wen, Yung-lo, Hung-hsi, and Hsüan-te reigns, 1399–1435". The Cambridge History of China, Volume 7: The Ming Dynasty, 1368–1644, Part 1. Cambridge: Cambridge University Press. ISBN9780521243322.
Dreyer, Edward L. (2007). Zheng He: China and the Oceans in the Early Ming Dynasty, 1405–1433. New York: Pearson Longman. ISBN9780321084439.