Molly

Yep, they're generally silly though. The split-infinitives one is particularly so - around the 17th century, it became fashionable in England to publish grammars of English, which tended to compare it to Latin grammar (which everyone learnt at school), and generally the more "logically deduced" prescriptive rules there were, the better the grammars sold, so lots of things got made up. For instance, in Latin, you can't split infinitives (because the Latin infinitive is just one word, e.g. amare, "to love,") and at some point it was arbitrarily decided that this should also be the case for English, even though it's got two word infinitives. Which of course makes no sense.