<Tr> <Td> 20 . </Td> <Td> Tommy Burns </Td> <Td> 2 years, 10 months, 3 days </Td> <Td> Universal </Td> <Td> 11 </Td> </Tr> <Table> <Tr> <Th> </Th> <Th> Name </Th> <Th> Title reign </Th> <Th> Title recognition </Th> <Th> Successful defenses </Th> </Tr> <Tr> <Td> N / A </Td> <Td> Vitali Klitschko </Td> <Td> 9 years, 7 months, 22 days </Td> <Td> Full WBC - to - WBC Emeritus - to - Full WBC (+ The Ring vacated) </Td> <Td> 11 </Td> </Tr> <Tr> <Td> N / A </Td> <Td> Muhammad Ali </Td> <Td> 7 years, 0 months, 11 days </Td> <Td> The Ring / + lineal (+ WBA, + WBC) </Td> <Td> 11 </Td> </Tr> <Tr> <Td> N / A </Td> <Td> James Toney </Td> <Td> 4 Years, 5 months, 14 days </Td> <Td> IBA / IBU </Td> <Td> </Td> </Tr> <Tr> <Td> N / A </Td> <Td> Brian Nielsen </Td> <Td> 3 years, 7 months, 20 days </Td> <Td> IBO </Td> <Td> 5 </Td> </Tr> </Table> <Tr> <Th> </Th> <Th> Name </Th> <Th> Title reign </Th> <Th> Title recognition </Th> <Th> Successful defenses </Th> </Tr> <Tr> <Td> N / A </Td> <Td> Vitali Klitschko </Td> <Td> 9 years, 7 months, 22 days </Td> <Td> Full WBC - to - WBC Emeritus - to - Full WBC (+ The Ring vacated) </Td> <Td> 11 </Td> </Tr>

Who is the longest reigning boxing champion in history