Koniecpolski now recognized the need to reform his army and strengthen the firepower of its infantry and artillery to match the Swedes'. The Swedes, on the other hand, had learned the arts of cavalry charges and melée combat from the Poles. Overall the 1627 campaign had been favorable to the Commonwealth; Puck and Gniew had been retaken, Swedish plans had been thwarted, and the Swedish army had been weakened. The last major engagement of the year saw the surprising defeat of a Swedish flotilla by the small Polish Navy on 28 November 1627 at the Battle of Oliwa.