<Table> <Tr> <Th_colspan="2"> Arizona Diamondbacks </Th> </Tr> <Tr> <Td_colspan="2"> 2018 Arizona Diamondbacks season </Td> </Tr> <Tr> <Td_colspan="2"> Established in 1998 </Td> </Tr> <Tr> <Td_colspan="2"> <Table> <Tr> <Td> </Td> <Td> </Td> </Tr> <Tr> <Td> Team logo </Td> <Td> Cap insignia </Td> </Tr> </Table> </Td> </Tr> <Tr> <Th_colspan="2"> Major league affiliations </Th> </Tr> <Tr> <Td_colspan="2"> <Ul> <Li> National League (1998--present) <Ul> <Li> West Division (1998--present) </Li> <Li> </Li> </Ul> </Li> </Ul> <P> </P> </Td> </Tr> <Tr> <Th_colspan="2"> Current uniform </Th> </Tr> <Tr> <Td_colspan="2"> </Td> </Tr> <Tr> <Th> Retired numbers </Th> <Td> <Ul> <Li> 20 </Li> <Li> 51 </Li> <Li> 42 </Li> </Ul> </Td> </Tr> <Tr> <Th_colspan="2"> Colors </Th> </Tr> <Tr> <Td_colspan="2"> <Ul> <Li> Sedona Red, Sonoran Sand, Black, Teal, White </Li> </Ul> </Td> </Tr> <Tr> <Th_colspan="2"> Name </Th> </Tr> <Tr> <Td_colspan="2"> <Ul> <Li> Arizona Diamondbacks (1998--present) </Li> </Ul> </Td> </Tr> <Tr> <Th_colspan="2"> Other nicknames </Th> </Tr> <Tr> <Td_colspan="2"> <Ul> <Li> The D - backs, The Snakes, The Rattlesnakes </Li> </Ul> </Td> </Tr> <Tr> <Th_colspan="2"> Ballpark </Th> </Tr> <Tr> <Td_colspan="2"> <Ul> <Li> Chase Field (1998--present) <Ul> <Li> a.k.a. Bank One Ballpark (1998--2005) </Li> </Ul> </Li> </Ul> </Td> </Tr> <Tr> <Th_colspan="2"> Major league titles </Th> </Tr> <Tr> <Th> World Series titles (1) </Th> <Td> 2001 </Td> </Tr> <Tr> <Th> NL Pennants (1) </Th> <Td> 2001 </Td> </Tr> <Tr> <Th> West Division titles (5) </Th> <Td> <Ul> <Li> 1999 </Li> <Li> 2001 </Li> <Li> 2002 </Li> <Li> 2007 </Li> <Li> 2011 </Li> </Ul> </Td> </Tr> <Tr> <Th> Wild card berths (1) </Th> <Td> <Ul> <Li> 2017 </Li> </Ul> </Td> </Tr> <Tr> <Th_colspan="2"> Front office </Th> </Tr> <Tr> <Th> Owner (s) </Th> <Td> Ken Kendrick </Td> </Tr> <Tr> <Th> Manager </Th> <Td> Torey Lovullo </Td> </Tr> <Tr> <Th> General Manager </Th> <Td> Mike Hazen </Td> </Tr> <Tr> <Th> President of Baseball Operations </Th> <Td> Mike Hazen </Td> </Tr> </Table> <Tr> <Th_colspan="2"> Arizona Diamondbacks </Th> </Tr>

When did the diamondbacks become a baseball team