Geocentric model and planets were holes in invisible wheels surrounding Earth; through the holes, humans could see concealed fire. About the same time, Pythagoras thought that the Earth was a sphere (in accordance with observations of eclipses), but not at the center; they believed that it was in motion around an unseen fire. Later these views were combined, so most educated Greeks from the 4th century BC on thought that the Earth was a sphere at the center of the universe. In the 4th century BC, two influential Greek philosophers, Plato and his student Aristotle, wrote works based on the geocentric model.
Central bank may incorporate the word "Central" (for example, European Central Bank, Central Bank of Ireland, Central Bank of Brazil). In some countries, particularly in formerly Communist ones, the term national bank may be used to indicate both the monetary authority and the leading banking entity, such as the Soviet Union's Gosbank (state bank). In rare cases, central banks are styled "state" banks such as the State Bank of Pakistan and State Bank of Vietnam. Many countries have state-owned banks or other quasi-government entities that have entirely separate functions, such as financing imports and exports. In other countries, the term national bank