Delegates from the largely Catholic Irish National Teachers' Organisation (INTO) heard a fraternal speech from a Loyalist, while a Sinn Fein member of the Northern Ireland Assembly sat at the top table during lunch with the National Association of Head Teachers.
This was followed by another extraordinary example of new thinking when the Ulster Teachers' Union voted to affiliate to the Irish Congress of Trade Unions.
There is nothing strange about teacher unions joining the congress. INTO, for example, has been a member since its creation. What is significant about the latest decision is that the Ulster Teachers Union was created as a breakaway organisation from the all-Ireland INTO back in 1919 by dissident Protestant teachers.
The union went on to oppose Home Rule and has continued to operate only within the six counties of Northern Ireland since Partition in 1921. It has no members in the three Ulster counties that are part of the Republic.
The Social Democratic and Labour party has been jocularly referred to as the INTO at play because of its large number of Catholic teachers. Similarly the UTU might be described as the Unionist party at school because the two organisations have so many members in common.
UTU has backed non-sectarian policies for several years and has some Catholic members, especially in special schools where the union is strong. Two Catholic nuns attended the annual conference for several years, giving their co-religionists a high profile.
But sectarianism often raises its head on issues such as social need, where the allocation of extra money to largely Catholic schools causes some resentment.