Complex sentence: A British force consisting mainly of Corsicans, Maltese and Sicilians was driven from Capri in 1808, but British troops occupied several Greek and Dalmatian islands until the end of the wars.
Split into simpler sentences: A British force consisting mainly of Corsicans, Maltese and Sicilians was driven from Capri in 1808. The British retained the Greek islands until the end of the wars.