Not too long ago, I was teaching a class of apparently average U.S. adults about genealogy and in conjunction with talking about the availability of certain types of records, I happened to mention 1861. I got a lot of blank stares and so I repeated my reference to the date. Still no response. So I asked more directly, what happened between the years 1861 and 1865. Still no glimmer of comprehension. I then asked bluntly about the U.S. Civil War. Finally, there was glimmer of recognition and a question, "Is that when the war happened?"
The United States War Between the States or Civil War is one of those events that should be firmly implanted in the genealogical mind (at least for those genealogists who have ancestors in the United States during that time period). In fact, every country in the world has similar dates and events. The importance of these events and dates is that they are accompanied with significant accumulations of records. This is one key to discovering a broader range of records about our ancestors. The key is transforming a moderate knowledge of local and national history into a method of finding information not contained in any of the more commonly used documents or records.
Usually, genealogists are exhorted to learn about their local and national history as a way to "get to know" their ancestors. History is stories and stories add interest. But I have a tendency to look at history from an additional and more practical standpoint. History produces records and records produce genealogy. Knowing when the U.S. Civil War occurred in crucial in alerting the researcher to the possibility of finding a military record or other associated type of record about an ancestor or an ancestor's family member. Likewise, valuable records such as those for draft registration can provide insights not present in some other types of records.
If you live in Canada, you have Canada Day, the celebration of July 1, 1867 when the British North America Act (presently known as the Constitution Act of 1867 ) created Canada. Australians have their Australia Day celebrated annually on January 26th, it marks the anniversary of the 1788 arrival of the First Fleet of British Ships at Port Jackson, New South Wales, and the raising of the Flag of Great Britain at Sydney Cove by Governor Arthur Phillip. In the United States we celebrate July 4th each year to commemorate the signing of the Declaration of Independence. I could go one with more examples, but suffice it to say, each country has it major, national holidays.
From a genealogical research standpoint, each of these dates mark a transition from one governmental system to another or to a change in settlement. As these changes occur, new records are created and older record types may disappear. Other dates that can directly affect genealogical research are connected with social changes. In Denmark, for example, there was a transition from the use of patronymic surnames to family surnames during the time period from 1826 to 1870. As a result of this change, it becomes increasingly more time consuming to do research during this time period to discover the names of an ancestor's parents, It becomes more difficult to consistently predict the surnames across generations.because some of the surnames were arbitrarily chosen.
One time, I ran across a family tree with a reference to the birth of my third-great-grandfather that had him born in Cottonwood, Utah in 1777. Unless you know that the first permanent European settlers reached Utah in 1847, you might not see anything wrong with a date in the 1700s. Likewise, I see many references to birth and death dates for individuals who lived in England in the 1400s. With the exception of a few royal lines, dates this early in England are extremely scarce. Likewise, I see that many online family trees date back with lines that purport to be traced back to Adam. The date given is usually 4000 B.C. This is an interesting date with a lot of baggage and seriously at odds with nearly every early dated ruin and artifact. Some considered this arbitrary date to be the basis for a conflict between science and religion. Regardless of your personal beliefs about the the date, its incorporation into genealogical research is just plain silly.
Whatever the purpose of researching your family history, there are simply no written records that are even arguably accurate that connect anyone in the present to anyone mentioned in the Bible. Whatever you want to call family trees that go "back to Adam." They are not genealogy. But the issue does bring up the subject of time limits for genealogical research. Just as the earliest genealogically significant records in Utah date no further into the past than 1847, all other types of records have a temporal termination. You cannot document any pedigree back further than the records were kept in any given part of the world.
Meanwhile, the dates of wars, natural disasters, plagues, political boundary changes and all sorts of other events in history have a direct bearing on genealogical records. The events can either engender the creation of additional records or destroy existing ones. When you know a little bit about history, you just might avoid spending a lot of time looking for records that aren't there or unproductively searching in the wrong places for records that exist somewhere else.