Bertran de Born
Bertran de Born (1140-1214) is a troubadour who is remembered as being overly enamoured of war. Dante Alighieri reserves a place for him in hell as a sewer of discord, blaming him for the murder of Thomas Beckett. It is certainly true that Bertran considered war to be a vital part of the chivalric code, but his meddling in English politics would seem to be overstated as Bertran was mainly concerned with local affairs.
Of his life we know little more, other than the fact that he had 5 children and married at least twice.