In Genealogy, people can be identified with random numbers that can be more unique than a name. This may be a lost opportunity for a system that can indicate their pedigree.
Pedigree numbering has been done with the popular Ahnentafel and Henry systems. They are very different, separately. Putting them together offers many advantages. I have created the title to be “Ahnentry” as a melding of the two system names. I claim ownership of this system and permit any use by any party that is not using it for financial gain.
This is a combination of standard numbering systems that is used to number ancestors, descendants, and collateral relatives within one numbering system. It is a combination of the
- Ahnentafel assignment of an integer to the place of an ancestor in the generations of the tree, and the
- Henry descendency digits assigned to the ancestor’s placement within a generation.
The two numbers are separated by a decimal point in the number with the ancestor identifier coming first, then the descendency descriptor digits following. Ahnentry adds small letters to a number to refer to spouses of blood relatives, as is done by many genealogists. For example, the first spouse of 136A2 would be 136A2a, the second spouse, 136A2b.
There are two major compromises, affecting only birth order recognition:
1. The ancestor is assigned the number with zero-tenths. That is, they are 9.0, which takes them out of birth order for the Henry System, but is still easily traced through the family.
2. If a sibling is discovered after the family has been numbered, it is optional whether to renumber the tree to obey a strict birth order on number assignments.
More details and examples are given below.
The Ahnentafel Ancestor Numbering System
It is easy to see how this numbering system works by looking at a pedigree chart or family tree. The first person on the chart, whose direct line ancestors will be shown on the pedigree chart, is person number 1. The father of person number 1 is number 2; their mother is number 3. The ancestors in the next generation (grandparents) are assigned Ahnentafel numbers 4-7; the next (great-grandparents) 8-15. Since the number of people doubles in each generation of ancestors, the number of numbers assigned to each generation also doubles. If an ancestor is not known, the Ahnentafel number for that ancestor is reserved until that ancestor is found—you do not assign it to a different ancestor.
A sample Ahnentafel Report:
First Generation
1.0 Richard Chase
Second Generation (Parents)
2.0 George Chase
3.0 Ernstene Gertride
Third Generation (Grandparents)
4.0 Hathaway Chase
5.0 Angelina Ramp
6.0 Logan Gertride
7.0 Mable Westin
This is a very easy system to use, and it has some nice mathematical properties. Other than person number 1, male ancestors always have even numbers, and female ancestors always have odd numbers. An ancestor’s father will always have an Ahnentafel number two times his or her own Ahnentafel number. And an ancestor’s mother will always have an Ahnentafel number twice his or her own, plus one. Conversely, a male ancestor’s child, who is one of your direct line ancestors, will always have an Ahnentafel number that equals the ancestor’s Ahnentafel number divided by two. For the child of a female ancestor, you would first minus one, and then divide by two, to get the Ahnentafel number of her child who is your direct line ancestor.
If you understand this, you can navigate around in a text Ahnentafel chart as easy as you can a graphical pedigree chart.
The Henry Descendant Numbering System
The Henry Numbering System assigns the number 1 to the common ancestor. A second digit is added for each generation, with the number of the new digit indicating the birth order that person is of the previous ancestor. For example, the 5 children of ancestor 1 would be assigned the numbers 11, 12, 13, 14, and 15. If person 12 had three children, they would be assigned the numbers 121, 122, and 123. For more than ten children, a capital letters A, B, C, D, etc. can be used. Doing this also results in computers sorting the Henry numbers correctly.
If additional research uncovers previously unknown siblings (in contrast to children of known siblings), many people may also have to be renumbered in the Henry numbering system. So when it comes to deciding whether to keep family files organized alphabetically or by a genealogical numbering system, you may want to consider this.
Another nice aspect of the Henry numbering system is that the numbers can be used to determine the ancestry of a descendant, as well as determine relationships between people. You know that 233 and 234 are siblings, 2331 and 2341 are cousins, 23312 and 23413 are second cousins, etc.
_________
For more information on these and other numbering systems, see
- Pence, Richard, http://www.genealogy.org/~st-clair/numbers/welcome.html;
- Devine, Donn, “How to Number People in Pedigrees and Genealogies,” in Ancestry Newsletter (V 4, N 1, page 1);
- Dollarhide, William, Managing a Genealogical Project, revised, Baltimore: Genealogical Pub. Co., Inc., 1991.
_________
This text was extensively copied from “Bygones .9b User’s Manual” Bygones and Genealogical Filing Systems, 1999, pp. 25ff.
