Miller's obvious European ancestry was no guarantee of her free status. By this time many mixed-race children fathered by European males had been born into generations of slavery, and some were mostly white in ancestry. In Louisiana, for instance, early French colonists had often taken slave women as mistresses or common-law wives. Under the legal doctrine of "partus sequitur ventrum" (literally "the child follows the womb", also known as "partus"), the children were held as born into slavery, because their mothers were slaves. This principle had been incorporated into colonial and state laws since the 17th century.