Which powers were left to the king? What was important about the powers that remained with the king

I assume You refer to Magna Cartha Magna Cartha limited the power of the king to the status that moanrchs ahd in continental Europe (origin of Magna Cartha was that since William teh Conqueror king power was strong and centralised in comparission to the rest of Europe) so king had judical power of organising the justice system and be the one who had control over 'nation wide' courts as we would say today king ofcourse was also a sovereign who was repsonsible for protection of whole country so he was commander in chief, more or less king power according to Magna Cartha was similar to modern day American president