Ancestral Chart Concepts
The underlying premise of an ancestral chart is that every person has a biological/adopted father and mother. This is predictable and certain, generation after generation. These charts typically use “Ahnentafel”-numbers (German for pedigree numbers, devised by Michaël Eytzinger, an Austrian historian who published the system in 1590) to cater for the exponential growth in the numbers of people as generations increase. (https://thatsmaths.com/2015/11/12/numbering-the-family-tree/). This numbering system provides a systematic way to uniquely identify people and position them in the family structure, even if nothing else but their number is known initially. (See also https://familypedia.wikia.org/wiki/Ahnentafel )
An ancestral chart starts with a descendent or selected person, male or female, which becomes the base person, #1 - the first generation. This person can be yourself, an ancestor, or any person you may be interested in.
- Person #1 has a father (#2) and a mother (#3)
- Person #2 has a father (#4) and a mother (#5)
- Person #3 has a father (#6) and a mother (#7)
There is a rhythm to the numbering system: The base person is number 1; his/her father is given double this number and his/her mother double-plus-one; and this process can be repeated generation after generation. Males therefore always have an even number and females have odd numbers. The number of people double in every generation – leading to an exponential growth curve:
- Generation 1 - 1 person - #1
- Generation 2 - 2 people - #2, #3
- Generation 3 - 4 people - #4, #5, #6, #7
- Generation 4 - 8 people - #8, #9, #10, #11, #12, #13, #14, #15