Ahnentafel - Revision history

Christoph: /* Second method (binary representation) */

2022-01-13T08:03:18Z

‎Second method (binary representation)

Christoph: /* Reverse first method */

2022-01-13T08:02:38Z

‎Reverse first method

Christoph: /* First method */

2019-02-11T00:59:38Z

‎First method

Christoph: /* First method */

2019-02-11T00:57:55Z

‎First method

Christoph: /* External links */

2019-02-11T00:56:23Z

‎External links

Christoph at 05:53, 9 May 2007

2007-05-09T05:53:24Z

Christoph at 06:48, 10 February 2007

2007-02-10T06:48:28Z

New page

An '''Ahnentafel''' (or '''Ahnenreihe'''), also known as the '''Sosa-Stradonitz System''', is a genealogical numbering system that allows one to list a person's ancestors in a particular order. It is a construct used in genealogy to display a person's ancestry compactly, without the need for a diagram such as a family tree, which is particularly useful in situations where one may be restricted to using plain text, for example in e-mails or newsgroup articles. The term Ahnentafel is a loan word from the German language, however its German equivalent is ''Ahnenliste''. In German ''Ahnentafel'' means a genealogical chart showing the ancestors of one person in the form of a binary tree.

An Ahnentafel may also be called a '''Kekulé''' after Stephan Kekulé von Stradonitz, the genealogist.

An Ahnentafel is effectively a method for storing a binary tree in an array by listing the nodes in level-order. The subject of the Ahnentafel is listed as #1, their father as #2 and their mother as #3, then their grandparents as #4 to #7, and so on back through the generations. In this scheme, any person's father has double that person's number, and a person's mother has double the person's number plus one. Apart from #1, who can be male or female, all even-numbered persons are male, and all odd-numbered persons are female. Using this knowledge, you can find out some things without having to compile a list.

==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:

{| {| class="wikitable"
|-
| align="center" | 116/2=58
| align="center" | 58/2=29
| align="center" | 29-1=28/2=14
| align="center" | 14/2=7
| align="center" | 7-1=6/2=3
| align="center" | 3-1=2/2=1
|-
| align="center" | father
| align="center" | father
| align="center" | mother
| align="center" | father
| align="center" | mother
| align="center" | 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==

{| class="wikitable"
! decimal !! binary !! relation
|-
| align="right" | 1
| align="left" | 1
| align="left" | self
|-
| align="right" | 2
| align="left" | 10
| align="left" | self's father
|-
| align="right" | 3
| align="left" | 11
| align="left" | self's mother
|-
| align="right" | 4
| align="left" | 100
| align="left" | self's father's father
|-
| align="right" | 5
| align="left" | 101
| align="left" | self's father's mother
|-
| align="right" | 6
| align="left" | 110
| align="left" | self's mother's father
|-
| align="right" | 7
| align="left" | 111
| align="left" | self's mother's mother
|-
| align="right" | 8
| align="left" | 1000
| align="left" | self's father's father's father
|-
| align="right" | 9
| align="left" | 1001
| align="left" | self's father's father's mother
|-
| align="right" | 10
| align="left" | 1010
| align="left" | self's father's mother's father
|-
| align="right" | 11
| align="left" | 1011
| align="left" | self's father's mother's mother
|-
| align="right" | 12
| align="left" | 1100
| align="left" | self's mother's father's father
|-
| align="right" | 13
| align="left" | 1101
| align="left" | self's mother's father's mother
|-
| align="right" | 14
| align="left" | 1110
| align="left" | self's mother's mother's father
|-
| align="right" | 15
| align="left" | 1111
| align="left" | self's mother's mother's mother
|-
|}

==External links==
[[wikipedia:Ahnentafel]]

[[Category:Demography]]

@@ Line 49: / Line 49: @@
 #One starts out by seeing if the number is odd or even.
-#If it is odd, the last part of the relation is "mother," so subtract 1 and divide by 2.
+#If it is odd, the last part of the relation is "mother", so subtract 1 and divide by 2.
-#If it is even, the last part is "father," and one divides by 2.
+#If it is even, the last part is "father", and one divides by 2.
 #Repeat steps 2–3, and build back from the last word.
 #Once one gets to 1, one is done.

← Older revision		Revision as of 05:53, 9 May 2007
Line 148:		Line 148:

	[[Category:Demography]]		[[Category:Demography]]
		+	[[Category:Genealogy]]

@@ Line 32: / Line 32: @@
 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.
+: 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 us 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"

@@ Line 46: / Line 46: @@
 We can also work backwards and find what the relation is from the number.
-===First method===
+===Reverse first method===
-: 1. You start out by seeing if the number is odd or even.
+#One starts 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.
+#If it is odd, the last part of the relation is "mother," so subtract 1 and divide by 2.
-: 3. If it is even, the last part is "father," and you divide by 2.
+#If it is even, the last part is "father," and one divides by 2.
-: 4. Repeat steps 2-3, and build back from the last word.
+#Repeat steps 2–3, and build back from the last word.
-: 5. Once you get to 1, you are done.
+#Once one gets to 1, one is 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:
+On an ahnentafel of Prince William, John Wark is number 116. We follow the steps:
-{| {| class="wikitable"
+{| class="wikitable"
 |-
-| align="center" | 116/2=58
+| align="center" | 116/2&nbsp;=&nbsp;58
-| align="center" | 58/2=29
+| align="center" | 58/2&nbsp;=&nbsp;29
-| align="center" | 29-1=28/2=14
+| align="center" | 29&nbsp;−&nbsp;1&nbsp;=&nbsp;28 and 28/2&nbsp;=&nbsp;14
-| align="center" | 14/2=7
+| align="center" | 14/2&nbsp;=&nbsp;7
-| align="center" | 7-1=6/2=3
+| align="center" | 7&nbsp;−&nbsp;1&nbsp;=&nbsp;6 and 6/2&nbsp;=&nbsp;3
-| align="center" | 3-1=2/2=1
+| align="center" | 3&nbsp;−&nbsp;1&nbsp;=&nbsp;2 and 2/2&nbsp;=&nbsp;1
 |-
 | align="center" | father
@@ Line 73: / Line 73: @@
 |}
-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.
+We reverse that, and we get that #116, John Wark, is Prince William's mother's mother's father's mother's father's father.
 ===Second method (binary representation)===

@@ Line 13: / Line 13: @@
 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'''
+:1&times;2&nbsp;+&nbsp;1&nbsp;=&nbsp;3
 So, if we were to make a list of ancestry for Peter Phillips, Electress Sophia would be #7233.

@@ Line 145: / Line 145: @@
 ==External links==
-[[wikipedia:Ahnentafel]]
+* [[wikipedia:Ahnentafel]]
 [[Category:Demography]]
 [[Category:Genealogy]]