Open main menu

Gramps β

Genealogical Numbering Systems

A multitude of Genealogical Numbering Systems have been developed for indexing family trees and pedigree charts in text format. Each system provides a consistent method to determine the appropriate & predictable identifier for persons in a Family Tree.

Most systems assign identifiers relative to a focal person and are oriented towards Ancestors (an ascending system) or Descendants (a descending system).

The terminology used to refer to this focal person varies, including: subject, proband (from psychiatry & medical genetics; proposito for male proband or proposita for female proband), root node (graphing), progenitor/primogenitor (for descending genealogical numbering systems), de cujus (Latin term meaning 'about which').


Genealogical Numbering System Support

Simple numbering

Fig. .1 Descendant Report - descending generation numbering using Example.gramps

Ahnentafel Numbering System

(German for "ancestor table") A tabular layout of genealogical data using an ascending system for numbering pedigree ancestors starting with '1' at a focal person. The number of the father is double that of the child. The mother is double the child's number plus one.

Fig. .2 Ahnentafel Report - ascending numbering focused on Jennie S. Garner of Example.gramps


An Austrian nobleman, diplomat, historian, and publicist named Michaël Eytzinger (circa 1530-1598) introduced a new functional theory of numeration of ancestors in 1590 with the Cologne publication of the Thesaurus principum hac aetate in Europa viventium ("lexicon of officials in this age in Europe living"). The Ahnentafel (German for "ancestor table") was first illustrated with a 5 generation pedigree of Henry III of France on pages 146 and 147.

External Links


Also called the Kekulé (Kekule) numbering system


Spanish Genealogist Jerónimo de Sosa was a 17th-century Spanish Franciscan friar and a genealogist who based a genealogical numbering system of ancestors on the Ahnentafel numbering system first published by Michaël Eytzinger. Sosa's 1676 work Noticia de la gran casa de los marqueses de Villafranca established a standard.

The system was popularized on a large scale by Stephan Kekulé von Stradonitz (1863–1933) when he published his interpretation of Eytzinger's and Sosa's method in his Ahnentafel-Atlas: Ahnentafeln zu 32 Ahnen der Regenten Europas und ihrer Gemahlinnen, 1898–1904, containing 79 charts of the sovereigns of Europe and their wives. (In 1895, Kekulé's prominent organic chemist father was ennobled by Kaiser Wilhelm II of Germany, giving him the right to add "von Stradonitz" to his name, referring to a possession of his patrilineal ancestors in Stradonice, Bohemia.)

External Links


de Villiers

Also called the Pama numbering system

A descendant numbering numbering system that assigns letters to generations, and then appends family subgroup birth order numbers. Listed in outline form with a concatenated form used for inline references to the list. In concatenated form, the generations are separated by a decimal point.

Developed in South Africa by Christoffel Coetzee de Villiers 1850-1887 for use in the 1894 posthumous Geslachtregister der Oude Kaapsche Familien. Refined by Dr. Cornelis "Cor" Pama 1916-1994 for the 1966 translation, Genealogies of Old Cape Families.


Fig. .3 Numbering System example from R.B.Henry's ©1935 book

A descendant numbering system that assigns a birth-order digit for each successive generation since an arbitrary progenitor.

The Henry System is a descending system created by Reginald Buchanan Henry (1881-1969) created a numbering system assigning a number for his 1935 book, Genealogies of the Families of the Presidents. In the original book, each USA President began a new section as was a Progenitor. So they restated the generation count of the list. The President was #1 only if they were a firstborn child. Otherwise, the first digit indexing number was equal to that President's birth order. The progenitor's offspring would be Generation 2 and appended a birth order digit to the index in the 2nd place.

Most notations in the Henry System are a modern reincarnation. In the (outmoded) original Henry System, if there were more than 9 children, the tenth child is given the letter 'X' (in deference to X meaning ten in the Roman Numeral system) and the eleventh child starts alphabetical substitutions with letters A through V. So a 4 digit index of 64B3 would be a child of the fourth generation. That descendant would be described as the 3rd child of the 12th child of the 4th child of the progenitor. And the progenitor was 6th born in their family. The modern Henry System is adapted to computerized sorting and ignores the preconception of the Roman Numeral system. It extends the Hexadecimal numeral system scheme and starts the substitution with 'A' for ten. In the modern Henry system, the 64B3 would have an 11th born child in the 3rd generation spot.

The original book also used an outline form which successively indented for each generation. Although simple to comprehend, the Henry format is not accepted for most genealogical publications.

Modified Henry System

The Modified Henry system assumes a substitution scheme is too confusing. Instead, it uses parenthetical numbers if more than 9 offspring were in a generation. So, the modern Henry system example 64B3 (from the section above) would be represented as 64(11)3 in the Modified Henry system.

External Links

Meurgey de Tupigny

A descendant numbering system that assigns Roman numerals to generations, and then appends family subgroup birth order Arabic numbers with a hyphen. Listed in outline form, normally in conjunction with pedigree charts.

Developed in France by Jacques Meurgey de Tupigny 1891-1973 for single surname studies and hereditary nobility line studies. Initially published in the 1956 Guide des recherches généalogiques aux Archives nationales.

Modified Register

Also known as the NGSQ (National Genealogical Society Quarterly) system, "Record System" or the "Modified Register System" Descendant Numbering System

created in 1870 for use in the New England Historical and Genealogical Register (NEHGR) published by the New England Historic Genealogical Society. Adopted with a NGSQs

The big difference between the NGSQ and the Register Systems is that the Record (Modified Register) System only assign a new number for progeny that list descendants later in the index. The NGSQ System assigns a number to every child, whether or not that child is known to have progeny.

NGSQ breadcrumbs

The New England Historic Genealogical Society developed the NGSQ descendant numbering system as part of their report format. That presentation format is used for publishing in the “National Genealogical Society Quarterly” and the “New England Historical and Genealogical Register” Superficially, it is bears a little resemblance to the Reports -> Text Reports -> Detailed Descendant Book addon report (Although you tweak a bunch of options.)

Essentially, the format lays out the line of descent from a specific ancestor as breadcrumbs to the progenitor. The format identifies the generation number in superscript after the given name, only lists surnames to indicate a change, and has the surnames in Uppercase.. or small caps for the following example. So the 4 generations of breadcrumbs linking David Johnson to his maternal great-grandmother, née Alice Smith, might be:

David Jᴏʜɴsᴏɴ; Mary³; Bob² Jᴏɴᴇs; Alice¹ Sᴍɪᴛʜ

External Links

Other numbering systems

Hybrid Approaches

Comparative References

Articles comparing & contrasting merits of competing numbering sysytems

Development Resources

  • Add a 'numbering' data class - Gramps feature request 0004169
  • Show Kekule numbering in different views- Gramps feature request 0007955 (a functional enhancement has been stalled in code review since 2017)
  • PseudonymTree.gramps - example (gzip compressed) multi-generational Gramps format Tree that uses intuitive pseudonyms & IDs for testing & exploration use.