It was 1348 when the Black Death reached the Island, ravaging the population. The change in England to a written language in "English" was not taken up in Jersey, where Norman-French continued until the 20th-century. In July 1373, Bertrand du Guesclin overran Jersey and besieged Mont Orgueil. His troops succeeded in breaching the outer defences, forcing the garrison back to the keep. The garrison came to an agreement that they would surrender if not relieved by Michaelmas and du Guesclin sailed back to Brittany, leaving a small force to carry on the siege. An English relief fleet arrived in time. On 7 October 1406, 1,000 French men at arms led by Pero Nino, a Castilian nobleman turned corsair, invaded Jersey, landing at St Aubin's Bay and defeated the 3,000 defenders but failed to capture the island.