Saved by the bell is an idiom that in English means: rescued from a situation at the last possible moment. Like a boxer, who is down for the count but before the referee manages to count to ten, the bell rings, signalling the end of the round.

But the origin of this idiom is not in a boxing ring. It dates back to 1696, when John Hatfield, a guard at Windsor Castle was accused of falling asleep at his post. If found guilty, he would have been executed. In his defence, he claimed that he heard the bells at St. Paul's Cathedral ring 13 times at midnight. This appeared ludicrous, as the bells are only supposed to ring 12 times. But upon asking the townfolk, it was found that the bells did indeed ring 13 times. John was acquitted. He was 'saved by the bell'.