We see a date in a history book or on the web on some "official" website, and we think that this is probably accurate, the real deal, something we can trust and have confidence in.
Don't be too sure about that.
I am beginning to prepare for a talk I will give on my research into the family structure of St. Augustine, Florida, during the Second Spanish Period (1784-1820). The research I have done is extremely complex, and to sum it up in the 10 minutes I will have for my presentation is not possible. What I am planning to do is gather information about a particular day or particular week, depending on how much information there is for any day or week during that period, and present a picture of a typical day or week in St. Augustine sometime between 1784 and 1820. This will be a way to show the human, day-to-day side of the town, say some things about the family relationships and the world and town in which these relationships existed. It will be a bottom-up view of history rather than the traditional top-down view.
I have begun to gather this information, using a 3x5 index card -- yes, I am old school -- for each event on each date. Right now, I am looking at the file on the probate of the will and estate of James Ormond, for whom Ormond Beach, Florida was named. He settled in East Florida, near the former plantation of New Smyrna. He had a wife, Russell (yes, that was her name), neé Walker, and two sons, James Ormond II and Emanuel Walker Ormond. The probate file does not have a record in it which gives James Ormond's exact date of death. Hoping to find at least a tentative date which I might verify later in some other record, I went to the internet.
What I found there is a can of worms.
One website says he died in 1819. Another says 1817. However, the record I am using, his will and attendant documents which form the probate file, come from the East Florida Papers, a collection of original documents from East Florida (mainly St. Augustine) during the Second Spanish Period. The file starts off with a request from the widow Russell Ormond that the closed file on James Ormond's death be reopened, because she, with problems of health and distance, had not been able to come to St. Augustine soon after her husband died.
This request was received by the governor's scribe on 27 September 1809.
Where did the 1817 and 1819 years come from for his death? I do not know. Does someone have an original document with such a date on it? I do not know that, either. I hope I can find another original document which will have a more precise date.
In the meantime, when you come across historical dates in derivative sources, see if you can find an original source which will either corroborate or refute the derivative source's information. Do not just take it at face value.