Yesterday I recalled having heard the rule prohibiting sentence-final prepositions.

The false rule of English usage (not really a grammar rule) was invented by the poet Dryden, who was so obsessed by it that he re-edited all his earlier works to weed it out. So misguided. Even Bishop Lowth, probably the greatest 18th century normative grammarian, poked gentle fun at this "rule" by mildly denouncing it with a sentence that ended in a preposition.

Ceci n'est pas un seing.