Complex sentence: In 1765, Captain John Byron explored Saunders Island, on West Falkland, named the harbour Port Egmont, and claimed this and other islands for Britain on the grounds of prior discovery.
Split into simpler sentences: In 1765, Captain John Byron explored Saunders Island on West Falkland. He named the harbour Port Egmont, and claimed this and other islands for Britain, on the grounds of prior discovery.