Great though he was, Alfred could not outlast the sands of time. He died in 899, with his kingdom well in hand and ready to be handed off to his son, Edward (called the Elder). Edward proved up to the task of defending the hard-fought territory his dearly loved father won, beating back Danish incursions left and right (or so it seemed) for a number of years.
At first, though, Edward had to deal with a small rebellion led by his cousin Ethelwald, who just happened to have the support of the Danes of Northumbria and East Anglia. Ethelwald, it turned out, was a favorite of Eric, who had succeeded to the Danish kingship after Guthrum (the man who had agreed to Alfred’s terms under the Danelaw and who had agreed, further, to be Alfred’s godson) died. Ethelwald and Eric set up stirring up trouble, and they eventually broke the peace with a military jaunt into Wilshire.
In 906, Edward had to muster considerable strength to deal with a rather large Danish incursion into Kent and Essex. Ethelwald had taken his army from East Anglia and run right through Mercia, conquering an dpillaging along the way. Edward drove the invaders back and drove his defender-of-the-realm point home by signing a peace with both the Danes of East Anglia and the Kingdom of York, which at that time was Danish Northumbria.
Four years later, in 910, Edward’s men were again on the march, again in the north and this time also against the East Anglian Danes. Again, the Saxons prevailed. This time, it was hoped, the truce would last. Also at this time, Edward took advantage of the death of his brother-in-law, the elder of Mercia, to lay claim to Mercia. (Among the important towns Edward “inherited” were London and Oxford.)
But alas, the Danes grew restless again, as more and more reinforcements landed from eastern lands. Hordes from Northumbria stormed into Mercia in 911, and Edward himself marched out with his men to turn back the Danish invasion. That English victory stuck for awhile, giving both sides pause (and time to regroup and re-equip).
The peace held for a small number of years, but trouble brewed again in 917. This time, the result was impressive. The English, in mass numbers from both Wessex and Mercia, invaded and eventually conquered East Anglia.
From this victory until his death, in 925, King Edward I (the Elder) set about building forts, reinforcing walls, and generally protecting his realm from the next Danish invasion. (The fighting didn’t stop altogether, of course, but the large-scale battles are rather absent from this part of history.) The crowning achievement, as it were, of Edward’s reign came in 924, when he was proclaimed overlord by the King of Scotland and the King of Strathclyde.
Though Edward seldom gets the credit and never gets “Great” after his name, he was every bit the military strategist that his father was. He left his kingdom in good shape.