Anne Foley, the principal at Kennedy School in Somerville, Mass., sent an email to teachers warning them about celebrating Thanksgiving, the Boston Herald reported.

“When we were young we might have been able to claim ignorance of the atrocities that Christopher Columbus committed against the indigenous peoples,” Kennedy School Principal Anne Foley wrote.

“We can no longer do so. For many of us and our students celebrating this particular person is an insult and a slight to the people he annihilated. On the same lines, we need to be careful around the Thanksgiving Day time as well.”