==All cousin marriages==
[[File:all-cousin-marriages.png|thumb|right|400px|The start of a listing of cousin marriages of European royalty]]
Occasional examples are found in many family trees of cousins or other close relatives marrying each other. This display collects all the examples in a tree together. The display puts the names of the husband and wife alongside the names of their common ancestors with dates and places of marriage. The list is sorted by the closeness of the relationship and the date of the marriage.
The number in the "Descent" column shows the number of generations from the common ancestor on the husband and wife's side resepectively. First cousins are thus represented as 2:2, second cousins 3:3 etc. The reason for this is that it is possible to go lower. The picture at the right shows examples of nephew-niece marriages (1:2). Brother-sister incest is represented as 1:1 and father daughter incest as 0:1. The example of Louis XIV and Marie-Therese of Spain shows an example of double first-cousin marriage. Where only one of the ancestors is shared, a footnote annotation (*) is added in the descent column and only the common ancestor is shown.
The relationship can be explored by clicking on the husband or wife's name which will always show their marriage first followed by their other relationships. Clicking on an ancestor shows instead a descendancy tree in which the cousin marriage will appear twice. This also works where there is only one common ancestor.
Most examples are not as close as these, and involve more distant cousins. So 2:3 (or 3:2) is a first cousin once removed
. Although marriages between first cousins are illegal in many US states, more distant cousin marriages are permitted and may be more common than people expect. They sometimes occur in clusters and to make these easier to spot, when names are repeated an occurrence number is added in square brackets after the name - ,  etc. These are actually links to a filter which will produce a separate report for the person concerned .
[[File:Victoria_relations_to_Albert. png|thumb|right|400px|Victoria's relations to her husband Albert]]