Henry William Carless Davis, 1911 Encyclopædia Britannica, Volume 15… (1911)
“ Up to the year 1139 he follows closely the history written by his predecessor, Prior Richard; thenceforward he is an independent though not a very valuable authority. He is best informed as to the events of the north country; his want of care, when he ventures farther afield, may be illustrated by the fact that he places in 1145 King Stephen’s siege of Oxford, which really occurred in 1142. Even for northern affairs his chronology is faulty; from 1140 onwards his dates are uniformly one year too late. Prior Richard is not the only author to whom John is indebted ”
