the gate was originally named chengtianmen (), or "gate of accepting heavenly mandate", and it has been destroyed and rebuilt several times. the original building was first constructed in 1420 and was based on a gate of an imperial building in nanjing with the same name and hence inherited the name "chengtianmen". the gate was damaged by lightning in july, 1457, and was completely burnt down. in 1465, the chenghua emperor of the ming dynasty ordered zi gui (), the minister of works, to rebuild the gate, and the design was changed from the original paifang form to the gatehouse that is seen today. it suffered another blow in the war at the end of the ming dynasty, when in 1644 the gate was burnt down by rebels led by li zicheng. following the establishment of the qing dynasty and the manchu conquest of china proper, the gate was once again rebuilt, beginning in 1645, and was given its present name upon completion in 1651. the gate was reconstructed again between 1969 and 1970. the gate as it stood was by then 300 years old, and had badly deteriorated, partly due to heavy usage in the 1950s and 1960s. as the gate was a national symbol, zhou enlai ordered that the rebuilding was to be kept secret. the whole gate was covered in scaffolding, and the project was officially called a "renovation". the rebuilding aimed to leave the gate's external appearance unchanged while making it more resistant to earthquakes and featuring modern facilities such as an elevator, water supply and heating system.