If, like me, you become puzzled or just downright confused by all the different offices, posts, departments and so on of English medieval government (many of which still exist today), then the site below is very helpful for clearing the confusion. After all, is it not bewildering to find that ‘in the king’s presence’ doesn’t mean he was present at all? “From the reign of Edward I, a Chief Justice of Common Pleas headed the panel of judges. Common Pleas was known contemporarily as ‘the Bench’ (banc), while King’s Bench was called ‘Coram rege’ (in the presence of the King – although the King was not actually present.)”
I recommend a dip into Medieval English Government by J.P. Somerville.