In this king's traditional belief system, individuals had remarkable rights such as trial by jury, property rights, the right to keep and bear arms, and the sincere belief and practice that God did not choose rulers, the people did. These traditions sound basic to modern ears, but they seemed oddly quirky and even innovative in the 800s.
Extending the full spectrum of rights to the conquered Vikings, and their Welsh allies, was going to be a tough row to hoe, and the only solution Alfred could come up with was to develop a sort of referee who would have the power of the Crown to protect the rights of the individual against unequal justice or oppression. These officers would also collect taxes, giving them the power of the purse and further ensuring that the nobles would respect their authority and obligation to protect the people, and not the nobles.
Finally, this new position could raise an army, something the king had learned was essential to keep his people's freedom alive. Relatively small, ad hoc armies had allowed him to fight his way from defeat to final victory over the invading Vikings and the Welsh; the very people he now intended to make solid citizens in his unified kingdom; the land of the Angles … England.
This new position, created to protect the rights of the individual in the Anglo-Saxon tradition, he called "Sheriff," and according to the great historian David Hume, Alfred the Great chose only men with the most probity to hold this office. Probity is an antiquated word that means adherence to the highest principles and ideals; that gives you an idea how important the new office was in the king's plan to create a new society of remarkably free citizens.
We call him Alfred the Great because not only did he save his island nation from invasion, but he also created the very concept of a United Kingdom; a realm with unique concepts of justice and freedom that continue to this very day.