![](GenealogyProbability.jpg)
I put this graphic and explanation together to
explain some anomalies in the data when I look at the number of ancestors I
have, as compared to the number of ancestors that I should have compared to
the number of people in the world, in Europe and in Norway during these
times.
When considering how many ancestors one has, the answer appears to be
mathematically infinite. In reality, you need to understand a number of
practical factors when researching this. This graph helps illustrate the
concepts. The
graph has a number of illustrations:
- The World Population is
in red noting the world population from about year 1000 to the present. The
yellow arrows note some significant events in Norway that affect population
and genealogy studies. Specifically:
-
The Viking Age which ran from
about 800 A.D. to about 1200 A.D. During this time, the Vikings were widely
traveled and some picked up wives from other geographic regions. If you look
in this genealogy, you'll find Viking kings and their children intermarried
into much of Northern Europe, the British Isles and all the way south to
Spain, Portugal, and Italy as well as east to Kiev in the Ukraine (a trading
route to the Constantinople or Byzantium, as they called it ). My
"Norwegian" ancestry at this time is much broader than Norway. It includes
most of Europe, mostly the places I mentioned above. The royals are known,
few commoners are known during this period.
- The Black Plague was a
significant event in Europe, much of in in southern Norway. Notice the dip
in world population, even though the event was localized in Europe.
- The Reformation was a
significant event in world history. In Norway, for genealogists, it
signifies a time before which many of the common church records disappeared.
The records were destroyed or taken by the priests that were expelled (or
killed) as the churches were converted.
- Immigration from Norway took
place from the 1800's to early 1900s as the population grew and
unoccupied farmland was unavailable.
- Norway Population is
in green. It is a sliver
of information on the chart since the population in proportion to the world
is a very small percentage.
- Ancestors are a
calculated figure which assumes that each person has two parents (Duh!), and
each generation spans about 30 years on average. One way to look at this
brown filled curve is to think of it as how many of your ancestors were born
after a certain year. None of my ancestors were born after 1930, 2 were born
after 1900, 4 were born after 1870, etc.
The rest is explained below.
The world population in the last thousand years has grown roughly
exponentially to it’s current count of about 4.2 Billion (2002). The
population of Norway is about 4 million, just a blip at the bottom of the
chart.
In the year 1000, it is estimated by most scholars that the world population
was about 225 million. Norway had about 200,000, but that is not even sure,
it may have been far less. In any case, the population of Norway is about
one tenth of one percent of the world, for the last thousand years according
to my research..
Mathematically, your ancestors double in count every generation…2 parents, 4
grandparents, 8 great grandparents, etc. 30 generations would yield over 2
billion 31st grandparents
(230 = 2,147,483,648).
Obviously there is a conflict here. How can one have two billion ancestors
in a population of 200 million, one tenth of the possibility, and much less
when you consider that we are researching a population of limited travel
[assuming that most of the population didn't travel, clearly the vikings
were well traveled at that period of time]…we are researching a population
of a few hundred thousand n all of Europe at most.
There are a few implications in this observation:
-
1)we
are related to the same people in multiple ways. In the year 1000, you may
have descended from a few thousands of couples rather than millions. The smaller the area of your
origin (i.e., Norway), the more likely this is. Someone with a Chinese
Father and Swedish Mother has a more likelihood of diversity, of course.
In my case, the origins of my people point to southern Norway.
-
2)The
farther back we go, the more likely we are related to other Norwegians. As
30th generation
descendants, we are likely related through these common ancestors.
3)
-
2 billion ancestors out of a population of 200 million means we have a
good chance of being related to everyone at that time. Since the
population of the Nordic areas is closer to 100,000 (about 50,000 are
men). Having a 31st generation
ancestor (one of 1 billion men), in a population of 50,000 means that
there are 20,000 chances (1Billion divided by 50 thousand) to be related
to a specific ancestor at least once.
Said in a different way, the probability of being related to any one person in
the Scandinavia area in the year 1000 is about one chance in 50,000. You
have 1 billion chances to be related at least once.
Some papers have suggested that in 30 generations, you are likely to be
descended from 25,000 unique people, not billions. That would imply that
each unique person is related to you in 40,000 different ways.
---------------------------
This chart shows another interesting observation.
The world population takes a dip in the 1300s. This coincides with
the black plague in Europe, which wiped out up to 1/3 of the population in
some areas. In Norway, it wiped out whole farms, leaving them empty for
hundreds of years in some cases.
©2000,2003 Ken Larson.
Please credit the sources given in any use of this
material.