Beginning in 1405, the Yongle Emperor entrusted his favored eunuch commander Zheng He (1371–1433) as the admiral for a gigantic new fleet of ships designated for international tributary missions. The Chinese had sent diplomatic missions over land since the Han dynasty (202 BCE – 220 CE) and engaged in private overseas trade, but these missions were unprecedented in grandeur and scale. To service seven different tributary voyages, the Nanjing shipyards constructed two thousand vessels from 1403 to 1419, including treasure ships measuring 112 m (370 ft) to 134 m (440 ft) in length and 45 m (150 ft) to 54 m (180 ft) in width.