of Malmesbury, William (Willelmus Malmesbiriensis. De Antiquitæ/Antiquitate Glastonie(nsis) Ecclesie/Ecclesia(e) (On Antiquity of Glastonbury Church). AD 1117:

Robinson, Joseph Armitage. “William of Malmesbury ‘On the Antiquity of Glastonbury’” in Somerset Historical Essays, pp1-25. London: Published for the British Academy by Humphrey Milford, Oxford University Press, 1921.
https://ia801604.us.archive.org/3/items/somersethistoric00robi/somersethistoric00robi.pdf