In May 1631, Grimm and his family were forced to flee Magdeburg, which was attacked by Count Tilly in the "Magdeburger Hochzeit". He escaped the Catholic forces only with the help of a Jesuit priest. From Magdeburg, he fled to Hamburg, where he briefly found employment at the St. Catharinen church. However, he was unable to find satisfactory long-term employment, and left Hamburg in search of better work.