 Heermann was born in Raudten (modern day Rudna) in Silesia, the fourth son of a middle-class Protestant family.None of his elder siblings had survived beyond childhood, so when the infant Heermann became very ill, his mother prayed that, if he survived, she would pay for him to study at university.He attended the local school in Raudten, and when his teacher Johannes Baumann left the school to become the local pastor in 1597, Heermann's parents took him to Wohlau, where he lived and studied with Jakob Fuchs, a doctor and apothecary.