I found this link looking for the origin of Dahej and came accross this. It is pretty interesting to read. Even though most information from anywhere is speculation, there is quite a lot of info to take into consideration.
http://www.hindubooks.org/sudheer_birodkar/hindu_history/practices1.html
Dahej or Hunda - Dowry and Bride-Price:
(This is just a small insert from the bottom of the page that discusses the origin of)
Note on Sati and Child-marriage
Sati, Child-marriage, Ghunghat, etc were largely caused by the arbitrary tryannical rule of the Sultans of Delhi. The temperament of theseSultans was a result of socio-cultural reasons. They had imbibed these their tryannical traits alongwith their religion from the Arabs who display traits like fanaticism and short-temperedness in their extreme. The reasons why these traits should exist among those Arabs who originate from the Saudi Arabian Peninsula are to be found in their harsh natural environment.
Saudi Arabia, the birth-place of Islam is devoid of fertile plains and river valleys which are congenial to the development of a settled civilized life. This was responsible for the atrophy of residents of the Arabian peninsula into barbarism, and their exclusion from civilization. The same cannot be said of the people of Mesopotamia, Assyria and Egypt who today consider themselves to be Arabs but were the founders of great riparian civilizations of the ancient world. The absence of a civilized way of life among the Arabs (from the Arabian peninsula) nourished the fanatical attitude which later became a characteristic of Islamic thought and way of life.
This attitude was transmitted to other people who were converted to Islam. Added to this was Islam's monotheistic character because of which Mohammedans regarded all other religions in exclusion from their own. This singularistic and exclusive character of monotheistic Islam precluded any possibility of assimilation into itself of other deities or forms of worship. And whenever it had the support or the force of arms, its fanatical and intolerant nature found brutal expression in the annihilative repression it unleashed whenever it came in contact with another religion or culture.
Such was the cultural lineage of the Sultans of Delhi. It made itself evident in the forcible conversion of peoples of other faiths to Islam at the point of the sword, destruction of places of worship belonging to other faiths, the imposition of Jazia tax on non-muslims and other policies whose objective was to stamp out all other religions and to Islamize the country.
Just one example of how things can get out of hand
