fitzgerald said:
Side point here,
Given the history of the Lord of the North, Earl isn't likely to be original noble rank.
Perhaps Duke, or Dux from the Roman Commander of men.
Ciao
From what we understand, Polarix existed a long time before King Arthur. However, that doesn't mean that Polarix 'started' with the power Arthur gave them. They were probably around, ruling the areas of the North anyway through virtue of being powerful. Then Morgana LeFey (or whatever) came and threatened to destroy things, and the Polarixes stood with Merlin and the Knights of the Round to defend the land, and then unite England together.
A lot of Polarixes probably died doing this, but in honor of that sacrifice, Arthur granted them real authority based off of his own, in place of the authority they held before by virtue of being the strongest wizards around. Where before people acknowledged Polarix because they were the most powerful clan of wizards around, and had been there for hundreds of years, no people acknowledged Polarix for all that, plus the fact that they were now actual knights and lords.
Polarix, of course, never 'really' recovered from the blow that had been dealt them, and slowly faded away as the world changed. Hence why the throne is empty.
Polarixes one last gasp was in the effort to unite England, which is fitting, seeing how the first thing the new heir is going to do is try to destroy magical government in the UK.