Primary documents are often the key to breaking down many brick walls. They can also raise more questions then answers for the inquiring mind. Being sure that one understands the historical context of the document will be the solution for many of these questions.
For example during my own research into the life of Cadwallader Jones, there is a primary document which records the following:
"This indenture made the (blank) in the year of our Lord according to the computation used in England One thousand six hundred Eighty & one and in the year of the Reign of or:Soveraigne Lord Charles the second &c. the three and thirtieth..."
[ (Old) Rappahannock County Deed Book 1682-1686 pp. 6-10 ]
Okay I thought, the date was blank but the year was given 1681, and the document was recorded to be in the 33 year of the reign of Charles II. What? My previous research into the JONES surname had recorded that Charles II only reigned for 24 years [1661-1685]. How could this be the 33rd year of his reign? [The following table shows the results of my study on the JONES surname for English Monarchs. Data was obtained from Pinnock's History of England, first published 1856.]
There you go I thought...it is often the one writing the history that gets to pick the dates. Choose wisely.