Ahnentafel

An ahnentafel is a special format for showing someone's ancestors. The starting individual is given the number 1. The father of someone on the list is double that person's number. So the subject being #1, his/her father would be #2 whose father would be #4, etc. The mother of a person is double their number plus 1. So the mother of the subject would be #3, whose mother would be #7.
Example:
*1 Subject
*2 Father
*3 Mother
*4 Father's Father
*5 Father's Mother
*6 Mother's Father
*7 Mother's Mother
In this way it is possible to make very long lists of ancestors but with a numbering system that allows you to keep track of who is who.
==How to find the Ahnentafel number, knowing the relation==
To find out what someone's number would be without compiling a list, you must first trace how they relate back to the person of interest, meaning you must record that they are their father's mother's mother's father's father's... Once you have done that, you can use two methods.
===First method===
Use the knowledge that a father's number will be twice the subject's number, or a mother's will be twice plus one, and just multiply and add to 1 accordingly. For instance, we can find out what number Electress Sophia of Hanover would be on an Ahnentafel of Peter Mark Andrew Phillips. Sophia is Peter's mother's mother's father's father's father's mother's father's father's father's father's father's mother. So, we multiply and add.
:::1*2+1=3*2+1=7*2=14*2=28*2=56*2+1=113*2=226*2=452*2=904*2=1808*2=3616*2+1=7233
So, if we were to make a list of ancestry for Peter Phillips, Electress Sophia would be #7233.
===Second method (binary representation)===
This is an elegant and concise way to visualize the genealogical chain between the subject and the ancestor.
: 1. Write down the digit "1", which represents the subject, and, writing from left to right, write "0" for each "father" and "1" for each "mother" in the relation, ending with the ancestor of interest. The result will be the binary representation of the ancestor's Ahnentafel number. Let's try with the Sophia example, translating the chain of relations into a chain of digits.
:::Sophia = "Peter's mother's mother's father's father's father's mother's father's father's father's father's father's mother"
:::Sophia = 1110001000001
: 2. If needed, convert the Ahnentafel number from its binary to its decimal form. A conversion tool might prove handy.
:::Sophia = 1110001000001 (binary)
:::Sophia = 7233 (decimal)
==How to find the relation, knowing the Ahnentafel number==
We can also work backwards and find what the relation is from the number.
===First method===
: 1. You start out by seeing if the number is odd or even.
: 2. If it is odd, the last part of the relation is "mother," and you subtract 1 and divide by 2.
: 3. If it is even, the last part is "father," and you divide by 2.
: 4. Repeat steps 2-3, and build back from the last word.
: 5. Once you get to 1, you are done.
So, let's see an example. On an Ahnentafel of HRH Prince William of Wales, Mr John Wark is number 116. We follow the steps:
116/2=58	58/2=29	29-1=28/2=14	14/2=7	7-1=6/2=3	3-1=2/2=1
father 	father 	mother 	father	mother 	mother
We reverse that, and we get that #116, Mr John Wark, is Prince William's mother's mother's father's mother's father's father.
===Second method (binary representation)===
:1. Convert the Ahnentafel number from decimal to binary.
:::Mr John Wark = 116 (decimal)
:::Mr John Wark = 1110100 (binary)
:2. Replace the leftmost "1" with the subject's name and replace each following "0" and "1" with "father" and "mother" respectively.
:::Mr John Wark = 1110100
:::Mr John Wark = "Prince William's mother's mother's father's mother's father's father"
==Demonstration==
decimal	binary	relation
1 	1 	self
2 	10 	self's father
3 	11 	self's mother
4 	100 	self's father's father
5 	101 	self's father's mother
6 	110 	self's mother's father
7 	111 	self's mother's mother
8 	1000 	self's father's father's father
9 	1001 	self's father's father's mother
10 	1010 	self's father's mother's father
11 	1011 	self's father's mother's mother
12 	1100 	self's mother's father's father
13 	1101 	self's mother's father's mother
14 	1110 	self's mother's mother's father
15 	1111 	self's mother's mother's mother
==Example==
For a real-life example, here is an ahnentafel of HRH Prince William of Wales, listing all of his ancestors up to his great-great-great-grandparents.
# William Arthur Philip Louis Windsor, Prince of Wales (1982) (born June 21, 1982)
# HRH The Prince Charles, Prince of Wales (born November 14, 1948)
# Diana Frances Spencer, Princess of Wales (1961-1997) (July 1, 1961 – August 31, 1997)
# Prince Philip, Duke of Edinburgh (1921) (born June 10, 1921)
# Elizabeth II of the United Kingdom (1926) (born April 21, 1926)
# Edward John Spencer, 8th Earl Spencer (1924-1992) (January 24, 1924 – March 29, 1992)
# Frances Ruth Burke Roche (1936-2004) (January 20, 1936 – June 3, 2004)
# HRH Prince Andrew of Greece and Denmark (January 20, 1882 – December 3, 1944)
# Princess Alice of Battenberg (1885-1969) (February 25, 1885 – December 5, 1969)
# George VI of the United Kingdom (1895-1952) (December 14, 1895 – February 6, 1952)
# Elizabeth Angela Marguerite Bowes-Lyon (1900-2002) (August 4, 1900 – March 30, 2002)
# Albert Edward John Spencer, 7th Earl Spencer (1892-1975) (May 23, 1892 – June 9, 1975)
# Cynthia Spencer, Countess Spencer née Lady Cynthia Hamilton (August 16, 1897 – December 4, 1972)
# Edmund Burke Roche, 4th Baron Fermoy (May 15, 1885 – July 8, 1955)
# Ruth Burke Roche, Baroness Fermoy née Miss Ruth Gill (October 2, 1908 – July 6, 1993)
# HM King George I of the Hellenes (December 24, 1845 – March 18, 1913)
# HM Queen Olga of Greece née HIH Grand Duchess Olga Konstantinovna of Russia (September 3, 1851 – June 18, 1926)
# HSH Prince Louis of Battenberg, later Louis Mountbatten, 1st Marquess of Milford Haven (May 24, 1854 – September 11, 1921)
# HGDH Princess Louis of Battenberg, later Victoria Mountbatten, Marchioness of Milford Haven née HGDH Princess Victoria of Hesse and by Rhine (April 5, 1863 – September 24, 1950)
# George V of the United Kingdom (1865-1936) (June 3, 1865 – January 20, 1936)
# Victoria Mary of Teck (1867-1953) (May 26, 1867 – March 24, 1953)
# Claude George Bowes-Lyon, 14th Earl of Strathmore and Kinghorne (1855-1944) (March 14, 1855 – November 7, 1944)
# Nina Bowes-Lyon, Countess of Strathmore and Kinghorne née Cecilia Cavendish-Bentinck (September 11, 1862 – June 23, 1938)
# Charles Robert Spencer, 6th Earl Spencer (October 30, 1857 – September 26, 1922)
# Margaret Spencer, Countess Spencer née The Hon Margaret Baring (December 14, 1868 – July 4, 1906)
# James Hamilton, 3rd Duke of Abercorn (November 30, 1869 – September 12, 1953)
# Rosalind Hamilton, Duchess of Abercorn née Lady Rosalind Bingham (February 26, 1869 – January 18, 1958)
# James Burke Roche, 3rd Baron Fermoy (July 28, 1852 – October 30, 1920)
# Frances, Lady Fermoy née Miss Frances Work (October 27, 1857 – January 26, 1947)
# Col William Smith Gill (February 16, 1865 – December 25, 1957)
# Ruth Littlejohn (December 4, 1879 – August 24, 1964)
# HM King Christian IX of Denmark (April 8, 1818 – January 29, 1906)
# HM Queen Luise of Denmark née HSH Princess Luise of Hesse-Kassel (September 7, 1817 – September 29, 1898)
# HIH Grand Duke Konstantin Nikolaevitch of Russia (September 9, 1827 – January 13, 1892)
# HIH Grand Duchess Aleksandra Iosifovna of Russia née HSH Princess Alexandra of Saxe-Altenburg (July 8, 1830 – June 23, 1911)
# HGDH Prince Alexander of Hesse and by Rhine (July 15, 1823 – December 15, 1888)
# HSH Princess Julia of Battenberg (November 12, 1825 – September 19, 1895)
# HRH Grand Duke Ludwig IV of Hesse and by Rhine (September 12, 1837 – March 13, 1892)
# HRH Grand Duchess Alice of Hesse and by Rhine née HRH The Princess Alice of the United Kingdom (April 25, 1843 – December 14, 1878)
# HM King Edward VII of the United Kingdom (November 9, 1841 – May 6, 1910)
# HM Queen Alexandra of the United Kingdom née HRH Princess Alexandra of Denmark (December 1, 1844 – November 20, 1925)
# HH Prince Franz, Duke of Teck (August 27, 1837 – January 21, 1900)
# HRH Princess Mary Adelaide, Duchess of Teck née HRH Princess Mary Adelaide of Cambridge (November 27, 1833 – October 27, 1897)
# Claude Bowes-Lyon, 13th Earl of Strathmore and Kinghorne (July 21, 1824 – February 16, 1904)
# Frances Bowes-Lyon, Countess of Strathmore and Kinghorne née Miss Frances Smith (1830 – February 5, 1922)
# Rev Charles Cavendish-Bentinck (November 8, 1817 – August 17, 1865)
# Carolina Burnaby (1833 – July 6, 1918)
# Frederick Spencer, 4th Earl Spencer (April 14, 1798 – December 27, 1857)
# Adelaide Spencer, Countess Spencer née Miss Adelaide Seymour (January 27, 1825 – October 29, 1877)
# Edward Baring, 1st Baron Revelstoke (April 13, 1828 – July 17, 1897)
# Louisa Baring, Baroness Revelstoke née Miss Louisa Bulteel (1839 – October 16, 1892)
# James Hamilton, 2nd Duke of Abercorn (August 24, 1838 – January 3, 1913)
# Mary Hamilton, Duchess of Abercorn née Lady Mary Curzon-Howe (July 23, 1848 – May 10, 1929)
# George Bingham, 4th Earl of Lucan (May 8, 1830 – June 5, 1914)
# Cecilia Bingham, Countess of Lucan née Lady Cecilia Gordon-Lennox (April 13, 1835 – October 5, 1910)
# Edmund Burke Roche, 1st Baron Fermoy (August 1815 – September 17, 1874)
# Elizabeth Burke Roche, Baroness Fermoy née Miss Elizabeth Boothby (August 9, 1821 – April 26, 1897)
# Frank Work (February 10, 1819 – March 16, 1911)
# Ellen Wood (July 18, 1831 – February 22, 1877)
# Alexander Ogston Gill
# Barbara Smith Marr (died ca. June 30, 1898)
# David Littlejohn (April 3, 1841 – May 11, 1924)
# Jane Crombie (died September 19, 1917)
# HSH Duke Friedrich Wilhelm of Schleswig-Holstein-Sonderburg-Glücksburg (January 4, 1785 – February 17, 1831)
# HSH Duchess Luise Karoline of Schleswig-Holstein-Sonderburg-Glücksburg née HSH Princess Luise Karoline of Hesse-Kassel (September 28, 1789 – March 13, 1867)
# HSH Landgrave Wilhelm of Hesse-Kassel (December 24, 1787 – September 5, 1867)
# HRH Landgravine Charlotte of Hesse-Kassel née HRH Princess Charlotte of Denmark (October 30, 1789 – March 28, 1864)
# HIM Emperor Nikolai I Pavlovitch of Russia (June 25, 1796 – February 18, 1855)
# HIM Empress Aleksandra Feodorovna of Russia née HRH Princess Charlotte of Prussia (July 13, 1798 – October 20, 1860)
# HSH Duke Josef of Saxe-Altenburg (August 27, 1789 – January 25, 1868)
# HSH Duchess Amelia of Saxe-Altenburg (June 28, 1799 – November 28, 1848)
# HRH Grand Duke Ludwig II of Hesse and by Rhine (December 26, 1777 – June 16, 1848)
# HRH Grand Duchess Wilhelmine of Hesse and by Rhine née HGDH Princess Wilhelmine of Baden (September 10, 1788 – January 27, 1836)
# Count Moritz von Hauke (October 26, 1775 – November 29, 1830)
# Countess Moritz von Hauke née Miss Sophie la Fontaine (1790 – August 27, 1831)
# HGDH Prince Karl of Hesse and by Rhine (April 23, 1809 – March 20, 1877)
# HRH Princess Karl of Hesse and by Rhine née HRH Princess Elizabeth of Prussia (June 18, 1815 – March 21, 1885)
# HRH Prince Albert of Saxe-Coburg-Gotha, Prince Consort (August 26, 1819 – December 14, 1861)
# HM Queen Victoria of the United Kingdom (May 24, 1819 – January 22, 1901)
# = 78
# = 79
# = 32
# = 33
# HRH Duke Alexander of Württemberg (September 9, 1804 – July 4, 1885)
# Countess Claudine Rhedey von Hohenstein (September 21, 1812 – October 1, 1841)
# HRH Prince Adolphus, Duke of Cambridge (February 24, 1774 – July 8, 1850
# HRH Princess Adolphus, Duchess of Cambridge née HSH Princess Auguste of Hesse-Kassel (July 25, 1797 – April 6, 1889)
# George Bowes-Lyon, Lord Glamis (February 6, 1801 – January 27, 1834)
# Charlotte Bowes-Lyon, Lady Glamis née Miss Charlotte Grimstead (1797 – January 19, 1881)
# Oswald Smith (July 7, 1794 – June 18, 1863)
# Henrietta Hodgson
# Lord Charles Cavendish-Bentinck (October 3, 1780 – April 28, 1826)
# Lady Charles Cavendish-Bentinck née Miss Anne Wellesley (1788 – March 19, 1875)
# Edwyn Burnaby (September 29, 1799 – July 18, 1867)
# Anne Salisbury (1805 – May 3, 1881)
# George Spencer, 2nd Earl Spencer (September 1, 1758 – November 10, 1834)
# Lavinia Spencer, Countess Spencer née Lady Lavinia Bingham (July 27, 1762 – June 8, 1831)
# Sir Horace Seymour (November 22, 1791 – November 23, 1851)
# Elizabeth Palk (died January 18, 1827)
# Henry Baring (January 18, 1776 – April 13, 1848)
# Cecilia Windham (February 16, 1803 – September 2, 1874)
# John Bulteel (died September 10, 1843)
# Elizabeth Grey (July 10, 1798 – November 8, 1880)
# James Hamilton, 1st Duke of Abercorn (January 21, 1811 – October 31, 1885)
# Louisa Hamilton, Duchess of Abercorn née Lady Louisa Russel (July 8, 1812 – March 31, 1905)
# Richard Curzon-Howe, 1st Earl Howe (December 11, 1796 – May 12, 1870)
# Anne Curzon-Howe, Countess Howe née Miss Anne Gore (March 8, 1817 – July 23, 1877)
# George Bingham, 3rd Earl of Lucan (April 16, 1800 – November 10, 1888)
# Anne Bingham, Countess of Lucan née Lady Anne Brudenell (June 29, 1809 – April 2, 1877)
# Charles Lennox, 5th Duke of Richmond and Lennox (August 3, 1791 – October 21, 1860)
# Caroline Gordon-Lennox, Duchess of Richmond and Lennox née Lady Caroline Paget (June 6, 1796 – March 12, 1874)
# Edward Roche (July 13, 1771 – March 21, 1855)
# Margaret Curtain (1786 – January 21, 1862)
# James Boothby (February 10, 1791 – October 28, 1850)
# Charlotte Cunningham (1799 – January 22, 1893)
# John Wark (1783 – April 16, 1823)
# Sarah Duncan Boude (December 15, 1790 – December 17, 1860)
# John Wood (July 29, 1785 – January 29, 1848)
# Eleanor Strong (ca. 1803 – July 9, 1863)
# David Gill
# Sarah Ogston
# William Smith Marr (November 27, 1810 – February 13, 1898)
# Helen Bean (1814/5 – July 20, 1852)
# William Littlejohn (August 12, 1803 – July 8, 1888)
# Janet Bentley (January 26, 1811 – October 1, 1848)
# James Crombie (January 13, 1810 – January 31, 1878)
# Katharine Forbes (December 1, 1812 – April 10, 1893)
==See also==
*Genealogical numbering systems
*:Category:Ahnentafels
*Template:Showinfo ahnentafel
*Template:Ahnentafel/5 - which uses Semantic Mediawiki to list ancestors
*Template:Ahnentafel-compact5 - which requires data to be added manually to cells
==External links==
*Ahnentafel Explained @ Ancestry.com
Category:Genealogy help
*