Note 536 — Chapter XVI · SOCIETY IN THE HEROIC AGE.
Reading edition
It is possibly due to the same cause that we meet with some curious marriages. Thus Alcinoos is married to his brother's daughter, and Iphidamas to his mother's sister. The former case offends against the principle of agnatic organisation, the latter against the cognatic. Some other heroes (e.g. Diomedes) seem to be in somewhat similar positions.