This entity type represents the current information known about an event that may have affected or involved one or more persons, groups or locations. E.g. it might contain information about: the San Francisco earthquake; an individual's birth - with details of their parents; the residence of a group of people in a location; a marriage ceremony; the merger of several railroads; the split of a US Territory location into State locations, etc.

Note this is not designed to record comprehensive data about historical events - rather to summarise them in relation to family history.

Note 2 - I have concerns if an EVENT can affect entities of mixed types - e.g. if an event can affect both PERSONs and LOCATIONs, say. This might make the data model tricky to negotiate. I am inclined to place a restriction on them to say an EVENT can only affect one type at once.

(Possible restriction that only one of the above three relationship types may hold at once for one EVENT - see above)