For four years Alfred had been unmolested by the Vikings, and had, beyond doubt, been working hard at the reorganization of his defences. Probably his military reforms were on the line of those which he effected later--recruiting the thegnhood, the military class, which was bound to follow the King to war, improving the arrangements for mobilizing the _land-fyrd_, and fortifying the chief towns and strategic points. But he did more than this. With a farsightedness which raises him above all early mediæval Western monarchs, save Charles the Great, he saw that the only sure way to curb the Vikings was to meet them at sea, and began to build a fleet. Under the date 875 the Chronicle says: ‘This summer went Ælfred the King out to sea with an armed fleet, and fought with seven pirate ships. One he took, and the others dispersed.’ That obscure sea-skirmish has a hallowed interest, for it was the first victory of the world-conquering British Navy. But as yet Alfred’s great reforms were in their infancy; his plans were only traced out, not yet executed. The flood was rising, and burst over devoted Wessex before the barriers which were to stay it had been raised. [Illustration: AN ANGLO-SAXON WEARING A HELMET OF LEATHER STRENGTHENED WITH METAL BANDS.] As soon as the season permitted, the ‘Great Army’ left Cambridge, made a night march to the Thames, and crossing it unopposed, rushed by forced marches across Wessex to Wareham, in Dorsetshire. It is to be noted that Winchester was avoided; evidently it had been fortified since the sack of 860. At Wareham the Danes were well placed for attacks on Wessex, and for a junction with their allies from Ireland, who came up immediately afterwards with a fleet of 120 ships. But Alfred was as prompt as his foes, and scarcely had the Vikings effected their junction when he blockaded Wareham with a large army. The result was that the Danes could only effect some sporadic raids of Dorset by sea. They finally extricated themselves by an act of treachery. They opened negotiations, and Alfred was ready to buy them off. Every year of immunity from pillage gained was to his advantage. The Viking chiefs swore a peculiarly solemn oath to observe the fact on a sacred ring or bracelet. Having thus thrown their enemies off their guard, the whole mounted part of the host sallied out from their entrenchments, cut their way through Alfred’s lines, and dashed through Dorset into Devon. Alfred, leaving part of his force to continue the blockade, promptly pursued, and finally besieged his treacherous foes in Exeter.