Alfred had short space to mourn his dead brother. The "Great Army" soon forced its way up from the Thames into Wiltshire, and beat the men of Wessex at Wilton. Then Alfred gave them great store of treasure to grant him peace, and they--since they found that the winning of Wessex cost so many hard blows--consented to turn aside for a space. But it was only in order to throw themselves on the neighbouring realm of Mercia. They dealt with it as they had already done with Deira and East Anglia. They defeated Burgred, its king, who fled away over sea and died at Rome; and then they took eastern Mercia and parcelled it out among themselves, while they gave its western half to an unwise thegn called Ceolwulf, who consented to be their vassal and proffered them a great tribute. It was not long, however, before they chased away him also. Now it was that there arose the great Danish towns in Mercia--Derby, Stamford, Leicester, Lincoln, and Nottingham, which, under the name of the "Five Boroughs," played a considerable part in English history for the next two centuries (876). [Sidenote: =Renewed invasion of Wessex.=] When Mercia had fallen, the Vikings turned once more against their old foes in Wessex. If only they could break down King Alfred's defences, they saw that the whole isle of Britain would be their own. So under the two kings, Guthrum and Hubba, they once more pushed southward beyond the Thames. There followed two years of desperate fighting (877-878). At first the invaders swept all before them. They took London, the greatest port of England, and Winchester, the capital of Wessex. Alfred, repeatedly beaten in battle, was forced westward, and driven to take refuge almost alone in the isle of Athelney, a marsh-girt spot in Somersetshire, between the Tone and the Parret. This was the scene of the celebrated legend of the burnt cakes. A curious memorial of Alfred's stay in Athelney is to be seen at Oxford--a gold and enamel locket bearing his name,[5] which was dug up in the island some nine hundred years after it was dropped by the wandering king. [Sidenote: =Defeat of the Danes.--Treaty of peace.=]