An Ahnentafel is a list of the ancestors of a person, numbered in such a way that the starting person is number 1, the father 2, mother 3, paternal grandfather 4, paternal grandmother 5, maternal grandfather and so on. It is also known as the Sosa-Stradonitz Method, for Jérôme de Sosa, the Spanish genealogist who popularized the numbering system in 1676 and Stephan Kekulé von Stradonitz, the German genealogist who published his interpretation of Sosa's method in 1898.

Set Your Family Tree Root

Log on to your online family tree as "Wizard", then select an individual and click "Update - Individual/Family". This will open a window that shows you a list of available update options. Click "Set to home individual" to set the selected individual as your family tree root.

Sosa numbers will be automatically assigned to the ancestors of your family tree root.

Clicking the Sosa number of any person will open a window that shows you a descendancy list.

Remove Your Family Tree Root

If needed, you can deactivate the numbering system. Select the "Online Family Tree - Manage - Expert Options" menu item then click "Remove the family tree root". Note that this will not remove the individual in your family tree!