Complex sentence: Separation of the island from Ireland was about 9000 BC while separation from the continent of Europe occurred around 6500 BC. English maritime history really starts with the Massaliote Periplus used by Phoenician traders in Iron Age Europe.
Split into simpler sentences: Separation of the island from Ireland was about 9000 BCE while separation from the continent of Europe occurred around 6500 BCE. British maritime history really starts with the Massaliote Periplus used by Phoenician traders in Iron Age Europe.