Complex sentence: Lithuanian Commonwealth Navy of 9 ships, mostly with aid from Danzig, which defeated a Swedish flotilla on 27 or 28 November 1627 (in the New Style calendar), at the battle of Oliwa near Danzig.
Split into simpler sentences: Lithuanian Commonwealth Navy of 9 ships, mostly with aid from the City of Danzig. He defeated a Swedish flotilla on 27 or 28 November 1627 (in the New Style calendar), at the battle of Oliwa near Danzig.