Understanding a sentence

In a legal sense something is material when it's relevant and important. Circumstances are all the facts connected with some matter. Circumstances include even minor details, subordinate and accessory facts.

As used here, for example, it essentially means:

all the facts in any way connected with a person, no matter how minor, so long as the fact is of some importance

This kind of legal definition calls for a fine distinction―perhaps even to the point of splitting hairs―to be made by arbiters of fact on a case by case basis.