Headda was consecrated between 758 and 770 and died between 770 and 777.[1]
Citations
^Fryde, et al. Handbook of British Chronology p. 217
References
Fryde, E. B.; Greenway, D. E.; Porter, S.; Roy, I. (1996). Handbook of British Chronology (Third revised ed.). Cambridge, UK: Cambridge University Press. ISBN0-521-56350-X.