The following is a canon of historical resources (often cited as though they were gospel) which may well be open to a considerable degree of question and must be used with the greatest of care:
- The History of the Kings of England by Geoffrey of Monmouth
- 1066 and All That: A Memorable History of England
- The Anglo-Saxon Chronicle
- The Calendar of Saints (in any edition)
- The Liber Pontificalis
- Plutarch, and other authors whose stated aim is to write exemplary biography
Also in citing historical resources keep in mind that what may generally regarded as truth by one generation of historians, may become extremely controversial by the next generation, who may not only have more complete facts, but may also be looking at the situation with a different set of historical biases. Case in point, lots of things that have been written about Chinese history, in particular the post-Song "decline", anything about Zheng He, the 1911 revolution, the interaction between China and Europe in the 19th century, the interaction between China and Europe before the 19th century.