The phrase 'The REST is history' is a popular idiom that implies that the story has been told and there is nothing left to say. It is often used to indicate that something has been completed or concluded. The crossword solution for this phrase is 'REST', which is a four-letter word meaning 'to take a break from activity'. This phrase is often used to signify the end of a story or event, suggesting that the details of what happened afterwards are not important.