Complex sentence: A British force quickly moved north to Foggia, which they took on September 27, and by the end of the month, the entire Apulia region and most of southern Italy were secured by Allied forces.
Split into simpler sentences: A British force quickly moved north to Foggia, which they took on September 27. By the end of the month, the entire Apulia region and most of southern Italy had been secured by Allied forces.