 These works were often themselves influenced by earlier, pre-Reformation texts by the Church Fathers, especially Bernard of Clairvaux, Augustine and Anselm of Canterbury.Heermann’s most influential work of devotional poetry was "Devoti musica cordis" (1630), ‘music for a devout heart’, which combined hymns based on texts of the Church Fathers and writers such as Moller with hymns Heermann himself had composed.In addition to works of poetry, he also published collections of sermons.