Quest for an adequate genealogical numbering system
A common genealogical numbering system is Ahnentafel, or Kekulé. It is straightforward enough, the proband, or primary person, being #1. His father is number #2, and his mother #3. Because we have four grandparents and eight great-grandparents, the numbers allocated to them are 4-7 and 8-15 respectively. Direct male descendants receive even numbers, whereas the women are given odd ones. Traditionally, the generations are listed as well, whereby generation I is usually that of the proband’s parents. We normally choose ourselves (or a child or grandchild) as the proband. One of the problems, however, is that the scheme only allows us to categorise our ancestors, meaning that siblings, cousins, in-laws, etc. fall by the wayside.
For that reason, German genealogists nowadays sometimes use an expanded Ahnentafel system which functions as follows:
When numbering direct ancestors, we keep to the traditional method. As the proband, though, I like my generation to be “I”. As Ralph Moore, I have chosen to call my tree “RM”, so my ID is therefore RM I1, or simply I1 or even 1. Since I have two younger brothers, I can optionally extend my ID to I1a. My brothers Sam and Ned are, according to the order of birth, I1b and I1c. I can also add my wife, Jackie Lowndes, to the tree, giving her the ID: I1aP (“P” stands for “Partner”). If I were to re-marry, I could choose suffixes to distinguish between my wives: P1, P2, etc. My wife’s parents can also be included as: IIa.PF and IIa.PM (the suffixes stand for “partner’s father” [F] and partner’s mother [M]. Note that because my wife’s parents are of another generation, the Roman numeral changes from my generation (I) to II. My father, Gerald Moore, is II2, and my mother, Maggie Crowe, II3. Now, my mother has two younger siblings, Fred and Patricia, which means that we add a small letter to the number. I13, my mother, now becomes II3a, so that her siblings can also receive person IDs: II3b and II3c. My maternal uncle Fred Crowe’s wife, Ann Hastings, can be given the combination II3b.P. Her parents are consequently: III3b.PF and IIIb.PM. We can tell from the Roman numeral “III” that my uncle Fred’s in-laws are of my grandparents’ generation. Fred and Ann have a daughter, Tamara Crowe. Because she is of my generation, and her ID is based on my mother’s and her siblings’, she becomes I3b.1. To take matters further, Tamara Crowe marries John Brown, and they in turn have two children: Bob and Geoff. However, because their generation is “below” mine, we give them the IDs -II3b.1.1 and -II3b.1.2. Geoff, for example, is the second child (hence: 1.2) of Tamara Crowe, who in turn is the eldest daughter of my mother’s eldest brother of two, Fred. Geoff’s wife is -II3b1.2P, and his eldest child would be given the ID: –III3b1.2.1. As you can see, we can apply this system to a very large number of close and distant relatives. Although we still unfortunately do not have a standardised universal numbering system, this method is a fairly adequate solution to the dilemma faced by anyone who wishes to distinguish between relatives within a large extended family or clan.
Source: Doris Reuter, “Welche Ziffer für den Urgroßvater?” in Ahnenforschung (2010), pp. 38ff.
Ru McKay (McKay-Coxon-Fisher-McMillan trees)