A colleague has sent us the following query, and I thought I'd see what the experts of this body have to say on the matter:

Folks, I was enmeshed in Shakespeare's sonnet #54 and pointed out that "Mars his sword" reminds us the possessive apostrophe is there to show letters have been omitted, whereupon one student said he understood that was an urban legend. "John's Mini Cooper" did not historically replace "John his Mini," he said. I love it when students teach the teacher, but this one is new to me. Anybody know the real scoop???