Following the conquest of England, the Normans gradually sought to extend their conquests both to the remainder of the British Isles and additional lands on the Continent, particularly in modern-day France. Over time, this would evolve into a long-standing policy of expansionism pursued intermittently with steadily increasing levels of aggression by successive English dynasties. Beginning in the 12th century, the Normans began making serious incursions into Ireland. The completion of the conquest of Wales by Edward I in 1284 put Wales under the control of the English crown, although Edward's attempts to completely subjugate Ireland met with very limited success while the initial success of his conquest of Scotland was undone by English military defeat under his son, Edward II. Edward III (reigned 1327–1377) transformed the Kingdom of England into one of the most formidable military powers in Europe; his reign also saw vital developments in legislation and government—in particular the evolution of the English parliament. From the 1340s the kings of England also laid claim to the crown of France, but after the Hundred Years' War the English lost all their land on the continent, except for Calais. The subsequent outbreak of the Wars of the Roses in 1455 would ensure the English were never again in a position to seriously pursue their French claims.