The Metro Nashville Police Department said the fight started over the discipline of two children.

Principal Renita Perkins told police one child was having problems with another child on the school bus.

The principal told both children to stay away from each other or they wouldn’t ride the bus anymore.

Ericka Harris, the mother of one of the children involved, reportedly walked in and demanded to know if the principal yelled at her child.

Perkins told her what she said and let Harris know that a parent couldn’t tell her how to run her school, according to the affidavit.

Witnesses said Harris then punched Perkins in the face and threw a book at her.

Harris was arrested on Wednesday and booked into the Metro jail on an assault charge. She bonded out of jail Wednesday night.  READ MORE AT WSMV