Original sentence: As a consequence, some scholars argue that the Anglosaxons probably were able to conquer all of Britain in the second half of the VI century.Conquest that was temporarily stopped, according to scholar John Morris at the Battle of Mount Badon probably in 497 AD, when the legendary King Arthur obtained an historical British victory that was followed by nearly fifty years of peace.Historically the period is centered on the conquest of Britain by the Anglosaxons.When the Plague of Justinian reached Britain in trade boats from mainland Europe, it killed around 550 AD up to half of the native British population (who did a huge commerce with the Mediterranean affected by the Plague) but left the English colonists largely unscathed