Their chairman, Graeme Ball, said no one knows precisely how much colonial history is being taught in schools because it is not a requirement of the curriculum. Only one achievement objective deals with New Zealand's shared past, he said, and it is not compulsory.
History can be highly contentious but that is no reason for schools to avoid it. Rather, it is more reason to give every New Zealand child a grounding of factual knowledge that will enable them to discuss it.
The Prime Minister, who was at secondary school in the 1990s, says she was taught about our colonial history and believes there is a public expectation it is being taught in schools. She is right about that. She hopes the teachers' petition will prompt a conversation about history. It should.
National leader Simon Bridges wants our history taught in a "balanced" way. Former leader Don Brash, also at Waitangi this week, believes the scale of inter-tribal warfare before 1840 should be part of a an understanding of the context of the Treaty.
Colonial history as previously taught has undergone substantial revisions for settlements of Treaty grievances over the past 30 years. That phase is nearing an end and it ought now to be possible to find a balanced history for teaching in schools. Its conclusions will always be contentions, which is why we all need to study it.