Edgar died in 975, and was succeeded by Edward the Martyr, who reigned three years, and then gave place to Ethelred the Unready. Then followed the period of decadence which prepared the way for Danish supremacy. Ethelred adopted the fatal plan of buying off his invaders, the effect of which policy was to increase the numbers and the demands of his enemies. Accordingly, in 994, Sweyn, son of the King of Denmark, and Olaf, King of Norway, made a descent upon London and devastated Kent, Sussex, and Hampshire. Olaf was bought off with a payment of £16,000, but the Danes were insatiable. A truce, purchased by Ethelred in 1002, was brought to an abrupt conclusion by his own weakness and cruelty; for in that year he planned and effected the massacre of all the Danes in his dominions, on St. Brice's day. Among the victims was a sister of Sweyn of Denmark, and Sweyn's revenge was sharp and swift. In 1003 he laid Exeter waste, and in 1004 destroyed Norwich; and when two years later the "great fleet" of the Danes arrived off Sandwich, Ethelred was obliged to purchase peace with a supply of provisions and a sum of thirty thousand pounds. Great efforts were made during this truce to reconstruct the navy. The king commanded ships to be built throughout the country and levied taxes to pay for them. Within a year it is said that eight hundred ships, equipped with thirty thousand men, were ready for the national defence. But no armament can be strong that is directed by weak hands, and the want of a wise and vigorous leader led to internal quarrels, which effectually destroyed Ethelred's chances of successfully resisting the Danes. In 1013 Sweyn was practically king of England, and Ethelred fled to Normandy. In 1016 the death of Ethelred left Edmund Ironside his son, and Canute, the son of Sweyn of Denmark, rival candidates for the throne. After fighting two battles, they agreed to divide the kingdom between them; but the death of Edmund the same year left Canute the master of the whole. Under Canute, peace prevailed and commerce began to thrive. "Men from the Rhineland and from Normandy moored their vessels along the Thames, on whose rude wharves were piled a strange medley of goods: pepper and spices from the far East, crates of gloves and gay cloths, it may be from the Lombard looms, sacks of wool; ironwork, from Liège, butts of French wine and vinegar, and with them the rural products of the country itself--cheese, butter, lard and eggs, with live swine and fowls." Such was Canute's influence that it became unnecessary to maintain more than forty ships for the protection of the coast, and this number was afterwards reduced to sixteen. With the death of Canute the Danish rule began to collapse, and with the accession of Edward the Confessor the Danes resumed their aggressive expeditions, though with but little success. William of Normandy found England without a fleet, for Harold had been compelled to disband the navy from want of supplies;