 Though Waldorf schools are autonomous institutions not required to follow a prescribed curriculum (beyond those required by local governments) there are widely agreed upon guidelines for the Waldorf curriculum, supported by the schools' common principles.The schools offer a wide curriculum "governed by close observation and recording of what content motivates children at different ages" and including within it, for example, the English, Welsh and Northern Irish National Curriculum.The main academic subjects are introduced through up to two-hour morning lesson blocks that last for several weeks.