Ahnentafel (from German, meaning "ancestor table") is a word used to refer to a type of ancestry chart or list. The format follows a number system:

The home person is #1 on the chart, their parents are #2 (father) and #3 (mother). It follows a format afterward as 4. father's father, 5. father's mother, 6. mother's father, 7. mother's mother, etc. Above the home person (#1), all males on the chart have even numbers, all females have odd numbers. Double any person's number to get his or her father's number; add 1 to the result to get the mother's number.

An example chart:

Self
1. Self
Parents
2. Father
3. Mother
Grandparents
4. Father's father
5. Father's mother
6. Mother's father
7. Mother's mother
Great-grandparents
8. Father's father's father
9. Father's father's mother
10. Father's mother's father
11. Father's mother's mother
12. Mother's father's father
13. Mother's father's mother
14. Mother's mother's father
15. Mother's mother's mother

With each generation, the number of people doubles. Everyone has (biologically) 2 parents, 4 grandparents, 8 great-grandparents, 16 2nd-great-grandparents, 32 3rd-great-grandparents, etc, but marriages between related people produce duplication and reduce the total number of different people.

To figure out a person's father, double their number. To figure out a person's mother, double their number and add one. Example:

Start with number 8, your father's father's father (your great-grandfather). His father would be at number 16 (8 x 2 = 16) and mother at 17 (8 x 2 + 1 = 17). Number 17's mother is at 35 (17 x 2 + 1 = 35).

To figure out a person's child, take for example number 41, a female. Her husband on the chart would always be right before her (40). To figure out 40 and 41's child, divide the father's number in half to get 20. (40 / 2 = 20). This same method can be used to figure out grandchild, great-grandchild, etc. Using 40 and 41 again, we would have:

• Their child: 40 / 2 = 20
• Their grandchild: 40 / 4 = 10 (Person 10 married Person 11)
• Their great-grandchild: 40 / 8 = 5 (Person 5 married Person 4)

However, you cannot find a child descended from 40 and 41 after number 5. 40 and 41's great great grandchild is the child of 4 and 5. You must divide the 4 in half, to get 2. And 2 is the father of the home person. In other words, the 3rd-great-grandchild of 40 and 41 is number 1, the home person.

## Example construction

The following is an example of how one can set up an ahnentafel in list form. We will even add dates of birth and death, because an ahnnetafel on Familypedia should link to individual pages for as many people as possible.

Let's say you want to do an Ahnentafel on John Isaac Smith IV (1934). Let's say we know his parents are John Isaac Smith III (1902-1985) and Mary Alice Johnson (1904-1963). The home person is at number one, and their parents at numbers 2 and 3:

1. John Isaac Smith IV (1934)
Parents
2. John Isaac Smith III (1902-1985)
3. Mary Alice Johnson (1904-1963)

Perhaps his paternal grandparents are John Isaac Smith, Jr. (1863-1933) and Abigail Elizabeth Williams (1867-1941). And his maternal grandparents are Henry Johnson (1870-1951) and Anne Thompson (1871-1958). We would have:

1. John Isaac Smith IV (1934)
Parents
2. John Isaac Smith III (1902-1985)
3. Mary Alice Johnson (1904-1963)
Grandparents
4. John Isaac Smith, Jr. (1863-1933)
5. Abigail Elizabeth Williams (1867-1941)
6. Henry Johnson (1870-1951)
7. Anne Thompson (1871-1958)

Of course, this may seem easy to put together, but the more generations you go back, the more people there are for each generation. Take the great-grandparents generation for instance. It would be best to take a person farther down the chart, like Abigail Elizabeth Williams (1867-1941). Let's say her parents are Thomas Williams (1823-1870) and Margaret Taylor (1835-1902). Abigail's number is 5. 5 x 2 = 10, so Thomas is at 10. His wife is just next to him, at number 11. So now we have:

1. John Isaac Smith IV (1934)
Parents
2. John Isaac Smith III (1902-1985)
3. Mary Alice Johnson (1904-1963)
Grandparents
4. John Isaac Smith, Jr. (1863-1933)
5. Abigail Elizabeth Williams (1867-1941)
6. Henry Johnson (1870-1951)
7. Anne Thompson (1871-1958)
Great-grandparents
10. Thomas Williams (1823-1870)
11. Margaret Taylor (1835-1902)

Perhaps you wish to continue up Abigail's ancestors, before proceeding to the other grandparents on the list. Thomas is at number 10, so his father would be at number 20 (10 x 2 = 20) and his mother at number 21:

1. John Isaac Smith IV (1934)
Parents
2. John Isaac Smith III (1902-1985)
3. Mary Alice Johnson (1904-1963)
Grandparents
4. John Isaac Smith, Jr. (1863-1933)
5. Abigail Elizabeth Williams (1867-1941)
6. Henry Johnson (1870-1951)
7. Anne Thompson (1871-1958)
Great-grandparents
10. Thomas Williams (1823-1870)
11. Margaret Taylor (1835-1902)
Great-great-Grandparents (often called "2/great-grandparents" for convenience)
20. Joseph Williams (1792-1862)
21. Isabel Olson (1799-1882)

The same processes can be done with other people on the chart. Perhaps Isabel's mother is unknown, but her maternal grandmother is known. Since Isabel is at number 21, her father is at number 42 (21 x 2 = 42) This makes her mother at number 43. Isabel's maternal grandfather is at number 86 (43 x 2 = 86) and so her maternal grandmother is at number 87:

1. John Isaac Smith IV (1934)
Parents
2. John Isaac Smith III (1902-1985)
3. Mary Alice Johnson (1904-1963)
Grandparents
4. John Isaac Smith, Jr. (1863-1933)
5. Abigail Elizabeth Williams (1867-1941)
6. Henry Johnson (1870-1951)
7. Anne Thompson (1871-1958)
Great-grandparents
10. Thomas Williams (1823-1870)
11. Margaret Taylor (1835-1902)
Great-great-grandparents
20. Joseph Williams (1792-1862)
21. Isabel Olson (1799-1882)
3/great-grandparents

(none listed yet)

4/great-grandparents
87. Catherine Richardson (1742-1784)

Eventually, you'll be able to fill in the chart's gaps and have a more complete looking ahnentafel:

1. John Isaac Smith IV (1934)
Parents
2. John Isaac Smith III (1902-1985)
3. Mary Alice Johnson (1904-1963)
Grandparents
4. John Isaac Smith, Jr. (1863-1933)
5. Abigail Elizabeth Williams (1867-1941)
6. Henry Johnson (1870-1951)
7. Anne Thompson (1871-1958)
Great-grandparents
8. John Isaac Smith (1830-1897)
9. Barbara Brown (1833-1902)
10. Thomas Williams (1823-1870)
11. Margaret Taylor (1835-1902)
12. Robert Johnson (1837-1909)
13. Josephine Ericson (1840-1932)
14. William Charles Thompson (1834-1901)
15. Maria García (1843-1920)
Great-great-grandparents
16. James John Smith (1802-1881)
17. Alice Davidson (1805-1890)
18. Robert Brown (1899-1851)
19. Elizabeth Wilson (1801-1877)
20. Joseph Williams (1792-1862)
21. Isabel Olson (1799-1882)
28. Charles Thompson (1792-1843)
29. Maria Müller (1798-1843)
3/great-grandparents
32. Thomas James Smith (1761-1820)
42. Robert Olson (1761-1799)
43. Ann Isaacson (1760-1832)
58. Johann Freidrich Müller (1755-1801)
59. Maria Schmidt (1758-1812)
4/great-grandparents
64. William Smith (1734-1800)
86. John Isaacson (1733-1802)
87. Catherine Richardson (1742-1784)
5/great-grandparents
128. John Smith (1701-1775)
6/great-grandparents
256. Timothy W. Smith (1674-1717)
7/great-grandparents
512. Edward Smith (1644-1701)

Cousin marriages will lead to situations where one person fills two or more numbered positions. At each position, you can add a note to say that the person with that number equals the person with another number. An example is in the ancestry of United States President John Calvin Coolidge, Jr. - see http://familypedia.wikia.com/wiki/Ancestries_of_the_U.S._Presidents#John_Calvin_Coolidge.2C_Jr.