Complex sentence: He served as commodore and commander-in-chief at the Leeward Islands during the War of the Austrian Succession and then took part in an operation to capture Louisbourg as part of the Louisbourg Expedition during the Seven Years' War.
Split into simpler sentences: He served as commodore and commander-in-chief at the Leeward Islands during the War of the Austrian Succession. He also served took part in an operation to capture Louisbourg as part of the Louisbourg Expedition during the Seven Years' War.