Travancore
In the erstwhile princely state of Travancore, in India, the male members of the Travancore Royal Family belonging to the Samanthan Nair caste were, under the existing matrilineal Marumakkathayam system of inheritance and family, permitted to contract marriages with women of the relatively inferior Illathu Nair caste only. These were morganatic marriages called Sambandhams wherein the children gained their mother's caste and family name, due to Marumakkathayam. Although they could not inherit the throne, they did receive the royal title of Thampi and were members of the Ammaveedus which ensured a comfortable living and all royal luxuries.
Read more about this topic: Morganatic Marriage