Cullmann became involved in revolutionary activity in Neustadt during the Revolution of 1848, and following the Bavarian crown's suppression of the rebellion with assistance from the Prussian Army, his business fell apart and he lost much of his wealth. In the years afterwards, he was able to re-establish himself but again lost his fortune following speculation during the Dano-Prussian War. Ruined in Germany, he began to look abroad for opportunity. His sights settled on the United States. However, at the time the American Civil War was ongoing, and fearing conscription, Cullmann temporarily settled in London in 1864. Not wanting to leave her family in Germany, his wife stayed behind.