After investigating the ice conditions, the king began his march on 30 January 1658 from Jutland across the strait of the Little Belt to Funen. Swedish troops defeated the Danes at Tybrind Vig and Iversnæs and occupied Funen after a few days. To avert the risk that his troops would be isolated on Funen, Charles X Gustav investigated the possibility of crossing the ice from the Great Belt to Zealand. On 5 February the ice at southern Funen was deemed sufficiently thick, and the king decided to cross to Langeland. He continued through Lolland and Falster and reached Zealand on 11 February. With Swedish troops standing from Copenhagen on 15 February, King Frederick III of Denmark chose to make an unconditional peace with Sweden, ending the Swedish campaign.