QUOTE : Some tribes maintain blood quantum, such as once-quarter proven blood degree from their tribe. Even so-called purely ‘descendancy’ tribes such as the Five Tribes with no blood quantum requirement jealously guard some proven, documentary link by blood to distant ancestors. More than any single BIA requirement, however, this criterion has proven troublesome for southeastern groups because of its reliance on on-Indian records and the confused (and confusing) nature of surviving documents.