> I use this numbering for my filing system. Have run across the > situation of having 1st cousins marrying. He is number 22 and she > is number 23. His mother would be 45 and her father would be 46. > This makes THEIR father both 90 and 92. So going further back, I'm > wondering, do I drop one number "line" or use both, with empty > lineage? > > "Roberta" <gmarob@gmail.com> I understand what you are saying as that you have encountered a problem trying to give each individual in a file a single unique number. As I understand it, there are two points to note about ahnentafel numbering: -- It is relative to a defined beginning individual. Therefore you can get into difficulty if you try to use it for numbering a collection of individuals. -- It defines both the relationship of an ancestor to that defined individual and also the ancestral route that links the two individuals. Therefore it is possible, as in your example, for an ancestor to have two or more ahnentafel numbers relative to the defined individual. This makes it not a useful system for permanent numbering of a collection of related individuals. Its main use seems to be in reports where you are looking at the ancestors of an individual. If you end up with multiple ahnentafel numbers, so be it, that is correct. Dropping one or the other may be a solution to your problem but will defeat the purpose of that numbering system and may lead to a confusing situation. The easiest solution is to allow affected ancestors to appear multiple times in the tree. This is okay for computer generated reports, but may not be convenient otherwise. I suspect you would be better off using some other system for unique numbering of the individuals. Incidentally, you don't have to go back many generations before ahnentafel numbers start to become so large as to be effectively meaningless to the reader. I imagine that the inventor only envisaged its use for small numbers of generations. Regards Peter Peter J Seymour <mozng@pjsey.demon.co.uk>