Two descendants of Black people once enslaved by a Native American tribe are asking a federal court in Oklahoma to force tribal leaders to issue them citizenship cards as ordered a year ago by a tribal court.

Civil rights attorney Damario Solomon-Simmons learned about the Tulsa Race Massacre during college.

While many across the country recognize Juneteenth as the end to the institution of slavery in America in 1865, some tribal nations in Oklahoma continued to own slaves until the following year, 1866.