<P> Seal of the Oregon Territory </P> <Tr> <Td_colspan="2"> Capital </Td> <Td> <Ul> <Li> Oregon City (1848--1851) </Li> <Li> Salem (1851--1855) </Li> <Li> Corvallis (1855) </Li> <Li> Salem (1855--1859) </Li> </Ul> </Td> </Tr> <Ul> <Li> Oregon City (1848--1851) </Li> <Li> Salem (1851--1855) </Li> <Li> Corvallis (1855) </Li> <Li> Salem (1855--1859) </Li> </Ul> <Li> Oregon City (1848--1851) </Li>

How did the oregon territory become part of the united states