Yongle Emperor
In old China, the Chinese emperors did not number their years from one place. Instead, they gave names to eras (groups of years) any time they wanted. Some emperors made 10 or more eras while they led China. Zhu Di started his era the year after he took Yingtian (now Nanjing) from his nephew the Jianwen Emperor in 1402. He said this was the 1st year of the "Era of Eternal Happiness", which sounds like Yǒnglè and is written  in traditional Chinese writing and  in the easier writing now used by the PRC. He only had this one era when he was emperor, so people also called him the "Emperor of the Yongle Era" or Yǒnglèdì ( or ).