<Tr> <Td> </Td> <Td> Republic declared </Td> <Td> September 2, 1945 </Td> </Tr> <Tr> <Td> </Td> <Td> Viet Minh reenters Hanoi </Td> <Td> October 10, 1954 </Td> </Tr> <Tr> <Td> </Td> <Td> PAVN enters Saigon </Td> <Td> April 30, 1975 </Td> </Tr> <Tr> <Td> </Td> <Td> North and South Vietnam merged </Td> <Td> July 2, 1976 </Td> </Tr>

Who became the chairman of the democratic republic of vietnam