 Impetus for this process of revision came from Martin Opitz's "Buch von der deutschen Poeterey" (1624), which acted both as a defence of German poetry and a set of guidelines on how German poetry should be composed.Johann Heermann can be regarded as one of the first German poets to write according to the rules set out in Opitz’s tract.As well as poetry based on the Gospels, Heermann also wrote poetry influenced by works of devotional literature, especially those by Valerius Herberger, Martin Moller and Johann Arndt.