And I just Wikipedia'd it. I was more or less in the ball park with my original recital. BUT! It had been too many years since I read Churchill's history, so I had some things wrong.

Among other things, it seems the reading test was abolished during Elizabeth I's reign, so the story about the modern malefactor getting off was wrong. Where I got that, I don't know.

The whole issue arose out of Becket's revolt, of sorts, against Henry VIII. In order to quiet the clerical uproar, certain offenses were given back to the Church to try and to discipline.

There were some crimes that were nonclergyable, as it were, treason being the one that sticks in my mind. Strangely enough, murder was not nonclergyable, but picking pockets was.   

Anyway, "benefit of clergy" did not refer to shriving before death.

Dave Oesterreich