Why were many Cherokee slaves "taken" to KS during the Civil War (C.W.)?

I am reviewing 10 application files of former Cherokee slaves who applied for inclusion on the Dawes Rolls. In testimony given by almost every single one they mention being taken to Kansas during the C.W. and returning to the Cherokee Nation by the 1866 deadline in order to qualify as freedmen on the Dawes Rolls.

What's up with that? Will someone please enlighten me? Thank you in advance for any information given.

[31 Aug 1999]