The link is what I believe to be a very interesting book (The Book of Bertram) written about 840 AD by a French monk (Bertram). It is written to King Charles the Bald, the grandson of Charlemagne. This small book is written to answer questions the king asked concerning the Lord’s Supper.
Bertram’s view of the Eucharist differs significantly from the Roman Catholic doctrine of Transubstantiation, which became official Church teaching at the 4th Lateran Council (1215 AD). The views expressed by Bertram are similar to those of the Protestant reformer, John Calvin some 700 years later. This book also played an important role in convincing a number of important English reformers to reject Transubstantiation and turn to the Reformed position on the Supper.