Continuity mistake: Al Pacino is accused of killing the 5 family leaders in 1950. In "Godfather part I" the killing of the 5 family leaders took place in 1955. (00:15:20)
Suggested correction: Michael is accused of "devising" the murder of the heads of the five families in 1950. Devising means planning, so while it may have taken about 5 years to successfully carry out, Michael begin planning the murders in 1950.
How is Michael accused of plotting the murder of the heads of the five families, as he himself is head of one of the families, yes five people die but Moe Green is not head of a New York family. It's been a long time since I have seen the film but that always stuck.
For alliteration purposes, five families seems to sound better then four families. Vito also asks for a meeting with the heads of the five families to stop the war, but he is one of the heads so he does not need to say five families, as if Tom would not think to include Vito in the meeting.
This is a common mistake made by viewers. Although there were, in actuality, 5 families in real life, there were 6 families. The script should have said "the other five families..." (or, better yet, just "the other families..." to make it clearer.
