After the Norman Conquest, English naval power waned and England suffered naval raids from the Vikings. In 1069, this allowed for the invasion and ravaging of England by Jarl Osborn (brother of King Svein Estridsson) and his sons. The lack of an organised navy came to a head during the First Barons' War, in which Prince Louis of France invaded England in support of northern barons. With King John unable to organise a navy, this meant the French landed at Sandwich unopposed in April 1216. John's flight to Winchester and his death later that year left the Earl of Pembroke as regent, and he was able to marshal ships to fight the French in the Battle of Sandwich in 1217 – one of the first major English battles at sea. The outbreak of the Hundred Years War emphasised the need for an English fleet. French plans for an invasion of England failed when Edward III of England destroyed the French fleet in the Battle of Sluys in 1340. England's naval forces could not prevent frequent raids on the south-coast ports by the French and their allies. Such raids halted only with the occupation of northern France by Henry V. A Scottish fleet existed by the reign of William the Lion. In the early 13th century there was a resurgence of Viking naval power in the region. The Vikings clashed with Scotland over control of the isles though Alexander III was ultimately successful in asserting Scottish control. The Scottish fleet was of particular import in repulsing English forces in the early 14th century. Age of Sail A standing "Navy Royal", with its own secretariat, dockyards and a permanent core of purpose-built warships, emerged during the reign of Henry VIII. Under Elizabeth I, England became involved in a war with Spain, which saw privately owned vessels combining with the Queen's ships in highly profitable raids against Spanish commerce and colonies. The Royal Navy was then used in 1588 to repulse the Spanish Armada, but the English Armada was lost the next year. In 1603, the Union of the Crowns created a personal union between England and Scotland. While the two remained distinct sovereign states for a further century, the two navies increasingly fought as a single force. During the early 17th century, England's relative naval power deteriorated until Charles I undertook a major programme of shipbuilding. His methods of financing the fleet