Several genealogical numbering systems have been widely adopted for presenting
family tree
A family tree, also called a genealogy
Genealogy (from el, γενεαλογία ' "study of family trees") is the study of , family history, and the tracing of their lineages. Genealogists use oral interviews, historical records, genetic a ...

s and
pedigree chart
A pedigree chart is a diagram that shows the occurrence and appearance of phenotype
In genetics
Genetics is a branch of biology
Biology is the natural science that studies life and living organisms, including their anatomy, phy ...
s in text format. Among the most popular numbering systems are:
Ahnentafel
An ''ahnentafel'' (German
German(s) may refer to:
Common uses
* of or related to Germany
* Germans, Germanic ethnic group, citizens of Germany or people of German ancestry
* For citizens of Germany, see also German nationality law
* German ...

(Sosa-Stradonitz Method), and the Register, NGSQ, Henry, d'Aboville, Meurgey de Tupigny, and de Villiers/Pama Systems .
Ascending numbering systems
Ahnentafel
Ahnentafel
An ''ahnentafel'' (German
German(s) may refer to:
Common uses
* of or related to Germany
* Germans, Germanic ethnic group, citizens of Germany or people of German ancestry
* For citizens of Germany, see also German nationality law
* German ...

, also known as the Eytzinger Method, Sosa Method, and Sosa-Stradonitz Method, allows for the numbering of ancestors beginning with a descendant. This system allows one to derive an ancestor's number without compiling the complete list, and allows one to derive an ancestor's relationship based on their number. The number of a person's father is twice their own number, and the number of a person's mother is twice their own, plus one. For instance, if John Smith is 10, his father is 20, and his mother is 21.
In order to readily have the generation stated for a certain person, the Ahnentafel numbering may be preceded by the generation. This method's usefulness becomes apparent when applied further back in the generations: e.g. ''08-146'', is a male preceding the subject by 7 (8-1) generations. This ancestor was the father of a woman (146/2=73) (in the genealogical line of the subject), who was the mother of a man (73/2=36.5), further down the line the father of a man (36/2=18), father of a woman (18/2=9), mother of a man (9/2=4.5), father of the subject's father (4/2=2). Hence, ''08-146'' is the subject's father's father's mother's father's father's mother's father.
The atree or Binary Ahnentafel method is based on the same numbering of nodes, but first converts the numbers to binary notation and then converts each 0 to M (for Male) and each 1 to F (for Female). The first character of each code (shown as X in the table below) is M if the subject is male and F if the subject is female. For example 5 becomes 101 and then FMF (or MMF if the subject is male). An advantage of this system is easier understanding of the genealogical path.
The first 15 codes in each system, identifying individuals in four generations, are as follows:
Surname methods
Genealogical writers sometimes choose to present ancestral lines by carrying back individuals with their spouses or single families generation by generation. The siblings of the individual or individuals studied may or may not be named for each family. This method is most popular in simplified single surname studies, however, allied surnames of major family branches may be carried back as well. In general, numbers are assigned only to the primary individual studied in each generation.
[Curran, Joan Ferris. ''Numbering Your Genealogy: Sound and Simple Systems.'' Arlington, Virginia: National Genealogical Society, 1992.]
Descending numbering systems
Register System
The Register System uses both
(1, 2, 3, 4) and
Roman numerals
Roman numerals are a that originated in and remained the usual way of writing numbers throughout Europe well into the . Numbers in this system are represented by combinations of letters from the . Modern style uses seven symbols, each with a ...
(i, ii, iii, iv). The system is organized by generation, i.e., generations are grouped separately.
The system was created in 1870 for use in the ''New England Historical and Genealogical Register'' published by the
. ''Register Style'', of which the numbering system is part, is one of two major styles used in the U.S. for compiling descending genealogies. (The other being the NGSQ System.)
[Curran, Joan Ferris, Madilyn Coen Crane, and John H. Wray.''Numbering Your Genealogy: Basic Systems, Complex Families, and International Kin.'' Arlington, Virginia: National Genealogical Society, 1999.]
(–''Generation One''–)
1 Progenitor
2 i Child
ii Child (no progeny)
iii Child (no progeny)
3 iv Child
(–''Generation Two''–)
2 Child
i Grandchild (no progeny)
ii Grandchild (no progeny)
3 Child
4 i Grandchild
(–''Generation Three''–)
4 Grandchild
5 i Great-grandchild
ii Great-grandchild (no progeny)
6 iii Great-grandchild
7 iv Great-grandchild
NGSQ System
The NGSQ System gets its name from the ''National Genealogical Society Quarterly'' published by the
National Genealogical Society headquartered in
Falls Church, Virginia
Falls Church is an independent city
An independent city or independent town is a city or town that does not form part of another general-purpose local government entity (such as a province).
Historical precursors
In the Holy Roman Empire
...
, which uses the method in its articles. It is sometimes called the "Record System" or the "Modified Register System" because it derives from the Register System. The most significant difference between the NGSQ and the Register Systems is in the method of numbering for children who are not carried forward into future generations: The NGSQ System assigns a number to every child, whether or not that child is known to have
, and the Register System does not. Other differences between the two systems are mostly stylistic.
(–''Generation One''–)
1 Progenitor
+ 2 i Child
3 ii Child (no progeny)
4 iii Child (no progeny)
+ 5 iv Child
(–''Generation Two''–)
2 Child
6 i Grandchild (no progeny)
7 ii Grandchild (no progeny)
5 Child
+ 8 i Grandchild
(–''Generation Three''–)
8 Grandchild
+ 9 i Great-grandchild
10 ii Great-grandchild (no progeny)
+ 11 iii Great-grandchild
+ 12 iv Great-grandchild
Henry System
The Henry System is a descending system created by
Reginald Buchanan Henry for a genealogy of the families of the presidents of the United States that he wrote in 1935. It can be organized either by generation or not. The system begins with 1. The oldest child becomes 11, the next child is 12, and so on. The oldest child of 11 is 111, the next 112, and so on. The system allows one to derive an ancestor's relationship based on their number. For example, 621 is the first child of 62, who is the second child of 6, who is the sixth child of his parents.
In the Henry System, when there are more than nine children, X is used for the 10th child, A is used for the 11th child, B is used for the 12th child, and so on. In the Modified Henry System, when there are more than nine children, numbers greater than nine are placed in parentheses.
Henry Modified Henry
1. Progenitor 1. Progenitor
11. Child 11. Child
111. Grandchild 111. Grandchild
1111. Great-grandchild 1111. Great-grandchild
1112. Great-grandchild 1112. Great-grandchild
112. Grandchild 112. Grandchild
12. Child 12. Child
121. Grandchild 121. Grandchild
1211. Great-grandchild 1211. Great-grandchild
1212. Great-grandchild 1212. Great-grandchild
122. Grandchild 122. Grandchild
1221. Great-grandchild 1221. Great-grandchild
123. Grandchild 123. Grandchild
124. Grandchild 124. Grandchild
125. Grandchild 125. Grandchild
126. Grandchild 126. Grandchild
127. Grandchild 127. Grandchild
128. Grandchild 128. Grandchild
129. Grandchild 129. Grandchild
12X. Grandchild 12(10). Grandchild
d'Aboville System
The d'Aboville System is a descending numbering method developed by
Jacques d'Aboville in 1940 that is very similar to the Henry System, widely used in
France
France (), officially the French Republic (french: link=no, République française), is a transcontinental country
This is a list of countries located on more than one continent
A continent is one of several large landmasses ...

. It can be organized either by generation or not. It differs from the Henry System in that periods are used to separate the generations and no changes in numbering are needed for families with more than nine children. For example:
1 Progenitor
1.1 Child
1.1.1 Grandchild
1.1.1.1 Great-grandchild
1.1.1.2 Great-grandchild
1.1.2 Grandchild
1.2 Child
1.2.1 Grandchild
1.2.1.1 Great-grandchild
1.2.1.2 Great-grandchild
1.2.2 Grandchild
1.2.2.1 Great-grandchild
1.2.3 Grandchild
1.2.4 Grandchild
1.2.5 Grandchild
1.2.6 Grandchild
1.2.7 Grandchild
1.2.8 Grandchild
1.2.9 Grandchild
1.2.10 Grandchild
The Huntington Family Association used this numbering system in their family memoir published in 1915, 25 years before Jacques d'Aboville is credited with inventing it. It may very well be true the Huntington family invented this numbering system.
Meurgey de Tupigny System
The Meurgey de Tupigny System is a simple numbering method used for single surname studies and hereditary
nobility
Nobility is a social class normally ranked immediately below Royal family, royalty and found in some societies that have a formal aristocracy (class), aristocracy. Nobility has often been an Estates of the realm, estate of the realm that p ...
line studies developed by of the
National Archives of France, published in 1953.
Each generation is identified by a Roman numeral (I, II, III, ...), and each child and cousin in the same generation carrying the same surname is identified by an Arabic numeral. The numbering system usually appears on or in conjunction with a pedigree chart. Example:
I Progenitor
II-1 Child
III-1 Grandchild
IV-1 Great-grandchild
IV-2 Great-grandchild
III-2 Grandchild
III-3 Grandchild
III-4 Grandchild
II-2 Child
III-5 Grandchild
IV-3 Great-grandchild
IV-4 Great-grandchild
IV-5 Great-grandchild
III-6 Grandchild
de Villiers/Pama System
The de Villiers/Pama System gives letters to generations, and then numbers children in birth order. For example:
a Progenitor
b1 Child
c1 Grandchild
d1 Great-grandchild
d2 Great-grandchild
c2 Grandchild
c3 Grandchild
b2 Child
c1 Grandchild
d1 Great-grandchild
d2 Great-grandchild
d3 Great-grandchild
c2 Grandchild
c3 Grandchild
In this system, b2.c3 is the third child of the second child, and is one of the progenitor's grandchildren.
The de Villiers/Pama system is the standard for genealogical works in
South Africa
South Africa, officially the Republic of South Africa (RSA), is the southernmost country in Africa. With over 60 million people, it is the world's 23rd-most populous nation and covers an area of . South Africa has three capital citie ...

. It was developed in the 19th century by
and used in his three volume ''Geslachtregister der Oude Kaapsche Familien'' (''Genealogies of Old Cape Families''). The system was refined by Dr.
Cornelis (Cor) Pama, one of the founding members of the
Genealogical Society of South Africa
The Genealogical Society of South Africa is a family history societyA family history society or genealogical society is a society
A society is a Social group, group of individuals involved in persistent Social relation, social interaction, o ...
.
Genealogical Society of South Africa
/ref>
See also
* Ancestral File Number
*Ahnentafel
An ''ahnentafel'' (German
German(s) may refer to:
Common uses
* of or related to Germany
* Germans, Germanic ethnic group, citizens of Germany or people of German ancestry
* For citizens of Germany, see also German nationality law
* German ...

*Cousin chart
Consanguinity ("blood relation", from Latin
Latin (, or , ) is a classical language belonging to the Italic languages, Italic branch of the Indo-European languages. Latin was originally spoken in the area around Rome, known as Latium. Through ...
(Table of consanguinity)
*Family tree
A family tree, also called a genealogy
Genealogy (from el, γενεαλογία ' "study of family trees") is the study of , family history, and the tracing of their lineages. Genealogists use oral interviews, historical records, genetic a ...

* Family tree mapping
*GEDCOM
GEDCOM ( ) (an acronym
An acronym is a word
In linguistics, a word of a spoken language can be defined as the smallest sequence of phonemes that can be uttered in isolation with semantic, objective or pragmatics, practical meaning (linguis ...
*
*Kinship terminology
Kinship terminology is the system used in language
A language is a structured system of communication
Communication (from Latin
Latin (, or , ) is a classical language belonging to the Italic languages, Italic branch of the Indo ...
*Pedigree chart
A pedigree chart is a diagram that shows the occurrence and appearance of phenotype
In genetics
Genetics is a branch of biology
Biology is the natural science that studies life and living organisms, including their anatomy, phy ...
*Pedigree collapse
In genealogy
Genealogy (from el, γενεαλογία ' "study of family trees") is the study of families
In human society, family (from la, familia) is a Social group, group of people related either by consanguinity (by recognized bi ...
References
;Notes
*About.com
Numbering Your Family Tree
Numbering Systems in Genealogy
by Richard A. Pence
External links
Encyclopedia of Genealogy-Numbering Systems
Numbering Systems in Genealogy
{{DEFAULTSORT:Genealogical Numbering Systems
Genealogy
Genealogy
Genealogy (from el, γενεαλογία ' "study of family trees") is the study of families
In human society, family (from la, familia) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinit ...