Date incerte (esempio Bernart de Ventadorn)

I have a problem with Bernart's date of birth and death. We know two dates that contain the events of his life: 1147 and 1170. So the birth took place in the first part of the century (before 1147) and the death between the end of the 12th and the beginning of the 13th (after 1170), but without precise data it is impossible for me to indicate a period that is not the 12th century.