 Under Johan Banér he served at the Battle of Wittstock on the left wing of the combined army of Banér and Field Marshal Alexander Leslie.He also served with distinction during the defence of Pomerania in 1637 and 1638, as well as at the Battle of Chemnitz and the raid into Bohemia in 1639.Illness, contracted during his imprisonment, compelled him to return to Sweden in 1641, where he was made a member of the Privy Council.